Proceedings - Lists of EPPO Standards - European and ...

2 nd International Workshop on 

Invasive Plants in the Mediterranean Type Regions of the World 

2010-08-02/06, Trabzon, Turkey 

Proceedings

Content 

Steering Committee of the Workshop…………….….…………………………. 4 

Foreword ……………………….…………………………………………….....…7 

Trabzon message………………………………………………………….….....…9 

Content of the Proceedings…………………….…………….………………... 11 

Presentation and outcomes of the thematic workshops..……………...……….19 

Oral presentations……………..………………….............................………….. 47 

Posters…………………………………………………………….……………..289 

Emails of participants………………………...……………………….….…… 437 

3

Steering Committee of the Workshop 

The steering committee is so far composed of experts from Mediterranean regions of the world: 

Local Committee 

Mr Güven Algün, Trabzon Agricultural Quarantine Directorate 

Mr Osman Nuri Baki, Province Directorate of Ministry of Agriculture and Rural Affairs 

Mr Doğan Işik, Karadeniz Agricultural Research Institute, Samsun 

Prof Atalay Sökmen, Karadeniz Technical University, Trabzon 

Mr Süleyman Türkseven, Ege University, Izmir 

Mr Ahmet Uludag, European Environment Agency 

Prof Huseyin Zengin, Igdir University, Igdir 

International Committee 

Mr Ahmet Aslan, Ministry of Agriculture and Rural Affairs, Turkey 

Mr Anoir Al Mouemar, University of Damas, Syria 

Mr Christian Bohren, Agroscope Changins, Switzerland 

Mr Giuseppe Brundu, University of Sassari, Italy 

Prof Ramiro Bustamante, University of Chile, Chile 

Ms Sarah Brunel, OEPP/EPPO 

Ms Laura Celesti-Grapow, University "La Sapienza di Roma", Italy 

Ms Costanza dal Cin D‘Agata, Park for the Preservation of Flora and Fauna, Greece 

Mr Joe DiTomaso, University of California, Davis, California 

Mr Pierre Ehret, French National Plant Protection Organization, France 

Mr Eladio Fernandez-Galiano, Council of Europe 

Mr Guillaume Fried, French National Plant Protection Organization, France 

Mr Piero Genovesi, ISSG 

Prof. Vernon Heywood, University of Reading, United Kingdom 

Mr Geoffrey Howard, IUCN 

Prof Inderjit, CEMDE, University of Delhi, India 

Ms Elizabete Marchante, University of Coimbra, Portugal 

Ms Lindsey Norgrove, CABI 

Prof Baruch Rubin, The Hebrew University of Jerusalem, Israel 

Prof Abdelkader Taleb, Institut Agronomique et Vétérinaire Hassan II, Morocco 

Prof David M. Richardson, University of Stellenbosch, South Africa 

Mr Andy Sheppard, CSIRO Entomology, Australia 

Ms Sarah Simons, Global Invasive Species Programme 

Ms Salma Talhouk, The American University of Beirut, Lebanon 

Ms Anna Traveset, Spanish Research Council (CSIC), Spain 

Mr Tuvia Yaacoby, Plant Protection and Inspection Services, Israel 

Prof Sinasi Yildirimli, Hacettepe University, Turkey 

4

Editors of the Proceedings 

Ms Sarah Brunel, EPPO (Editor in chief) 

Mr Ahmed Uludag, EEA 

Mr Eladio Fernandez-Galiano, Council of Europe 

Mr Giuseppe Brundu, University of Sassari, Italy 

Reviewers 

Prof. Mohamed Bouhache, Institut Agronomique et Vétérinaire Hassan II, Morocco 

Ms Madeleine Mc Mullen, EPPO 

Prof. Pavol Elias, Dept. Of Ecology, Slovak Agricultural University, Slovakia 

Mr Vladimir Vladimirov, Institute of Botany Bulgarian Academy Of Sciences, Bulgaria 

Ms Ernita van Wyck, South African National Biodiversity Institute, South Africa 

Mr. İlhan Üremiş, Mustafa Kemal University, Turkey 

Mr. Pierre Ehret, French Plant Protection Organization, France 

Ms Judith Lorraine Fisher, University of Western Australia/Fisher Research, Australia 

Ms Elizabete Marchante, University of Coimbra, Portugal 

Mr Guillaume Fried, French National Plant Protection Organization, France 

Prof. Ramiro O. Bustamante, University of Chile, Chile. 

5

Foreword 

At the 10th Conference of the Parties of the Convention on Biological Diversity, held in Nagoya 

(Japan) in 2010, world governments adopted targets aimed at reducing pressures on biological 

diversity. Target 9 concerned Invasive Alien Species, know to be one of the main causes of 

extinction of species at the global level: 

―: By 2020, invasive alien species and pathways are identified and prioritised, priority species are 

controlled or eradicated, and measures are in place to manage pathways to prevent their introduction and 

establishment‖, 

Mediterranean type regions are hotspots of biological diversity at the world level and thus an 

improved knowledge of how they are affected by invasive alien species and how to prevent their 

arrival and spread is vital to be able to preserve their biological richness. A First International 

Workshop on Invasive Plants in the Mediterranean Type Regions of the World was held in Mèze 

(France) from 25 to 27 May 2008, helping bring together information and expertise on the topic. 

(http://archives.eppo.org/MEETINGS/2005_meetings/workshop_invasive/workshop.htm ) 

This second Workshop, co-organized by the European and Mediterranean Plant Protection 

Organization, The European Environment Agency, the Council of Europe, Igdir University and 

The Turkish Ministry of Agriculture was held in Trabzon (Turkey), from 2 to 6 August 2010. 

It was attended by over 90 participants from 29 countries (Australia, Armenia, Azerbaijan, 

Bulgaria, Chile, Croatia, Czech Republic, France, Greece, Hungary, India, Iran, Israel, Italy, 

Lithuania, Malaysia, Morocco, Portugal, Saudi Arabia, Serbia, Slovakia, Slovenia, South Africa, 

Sudan, Syria, Switzerland, Tunisia, Turkey, UK, USA). Experts from the other Mediterranean 

Type Regions of the World (Northern Chile, California, the Cape Region of South Africa, and 

Western Australia) presented their experience with invasive species. 

The workshop consisted in plenary presentations and small working groups, allowing participants 

to network and to discuss current and future projects. The conclusions of all small working 

groups, as well as either full contributions or abstracts of oral or poster presentations are available 

in these proceedings. 

A statement was also made at the workshop: the Trabzon message, focusing on the need for more 

science and more conservation action on invasive alien species in Mediterranean- type regions. 

The 3rd workshop of that series should be organized in 2014 in Tunisia. 

The Editors. 

7

Trabzon message 

The participants of the 2 nd workshop on invasive alien plants in the Mediterranean type regions of 

the world meeting in Trabzon, Turkey, from 2 to 6 th of August 2010: 

1. Warmly thank Turkish authorities and the Igdir University for their warm welcome and 

excellent hosting of the meeting and the European Environment Agency, the European and 

Mediterranean Plant Protection Organization, and the Council of Europe for their support, as well 

as the sponsors. 

2. Recall the Mèze Declaration and note that Invasive Alien Plants are a major threat both to 

natural and semi-natural habitats and agriculture and that our societies would highly benefit from 

addressing the issue and taking further steps to control their spread and mitigate their impacts. 

3. Encourage governments, the scientific community, conservation practitioners, the agriculture 

profession, the horticulture industry, National Plant Protection Organizations, and other 

appropriate stakeholders to publicize and implement the recommendations below which are the 

result of discussions in the different workshops from this meeting: 

Promote awareness on IAP, targeting diverse public, by creating a well-planned and effective 

communication strategy, and organize a wide Mediterranean “cleanup day” including hands 

on activities to control IAP (2011 or 2012) which should be widely publicized; 

Encourage the elaboration of lists of priority alien plants as a tool to raise awareness on 

emergent invasive alien species by biogeographical zones, particularly in Mediterranean 

countries where global databases are lacking, as it is planned to be done by a number southern 

Mediterranean countries with the EPPO prioritization process; 

Promote the removal or eradication of invasive alien plants as a tool to be used as part of the 

integrated management of IAS, giving due consideration to its costs, feasibility and the health, 

economy and conservation gains; prioritize species and target habitats, monitor results and 

publicize and exchange information; 

Take necessary steps to make Codes of conduct on invasive alien plants better known and used 

and to encourage their use, establishing a dialogue with the horticulture industry and its 

customers (including managers involved in landscaping operation); use meetings of the 

horticulture industry such as the one to be held in Turkey in 2016 to draw their attention to the 

need of cooperation; publicize the Council of Europe/EPPO Code of conduct on horticulture and 

invasive alien plants, and translate it into different languages and adapt it nationally; 

Discourage the planting of Acacia species known to be invasive; establish a network to transfer 

knowledge so that management can be improved and risk assessment communicated; 

9

Encourage and support the inclusion and integration of North African countries in the European 

early warning system being developed by organizing a workshop targeting representatives of 

national authorities and academics so as to raise awareness and promote the increase in 

knowledge; 

Encourage cooperation on, training of specialists and early warning in the Black Sea region 

which is subject to high trade and fast spread of IAP and relatively difficult exchange of 

information; 

Promote early warning and rapid response systems, including at the local and/or regional level; 

create awareness among governments and international bodies on the need to deal soon and 

effectively with new invasive alien plants; promote flexible mechanisms of early response, based 

on local expertise and resources; work towards and integrated European system such as the one 

proposed by the EEA. 

Use risk assessment for the selection of biofuel crops, and monitor closely the plants that are 

used in order to assess their invasiveness in new cropping systems; 

Launch a questionnaire on the important invasive alien plants in arable areas in Mediterranean 

countries to be spread to the participants and any relevant contacts, analyze and update these data 

on the Internet; 

Focus research on new invasive alien plants under global change (e.g. aquacrop model of FAO); 

Support the preparation of national inventories and herbaria of IAP as useful tools for IAS 

national strategies and promote local and regional exchange of information. 

10

Thematic Workshops 

Section 1 : Plant invasions in the Mediterranean: where do we stand? 

Using the prioritization process for Mediterranean countries, Chaired by Mr Guillaume Fried and 

Ms Sarah Brunel……………………………………………………………………………………..20 

Alien trees in the Mediterranean countries: focussing on Acacia spp., Chaired by Ms Genevieve 

Thomson and Mr Giuseppe Brundu……………………………………………………………….22 

Similarities and differences between distribution of invasive alien plants in the Black Sea and 

Mediterranean area, Chaired by Mr Necmi Aksoy…………………………………...………….24 

Section 2 : Early warning 

Building an Early Detection Rapid Response (EDRR) for the Mediterranean, Chaired by Mr 

Kassim Al-Khatib and Mr Ahmet Uludag……………………………………………….……….26 

Identifying targets for eradication in the Mediterranean and eradication experiences, Chaired by 

Mr Eladio Fernandez Galiano…………………………………………………….……………….29 

Cooperation/inclusion of North African Countries in European early warning system, Chaired by 

Mr Mohamed Bouhache and Mr Riccardo Scalera……………….………….……………32 

Section 3: Communication, policies & strategies for tackling invasive alien plants 

Implementing Codes of conduct on horticulture and invasive alien plants for the Mediterranean, 

Chaired by Prof. Vernon Heywood……………………………………………………….……….34 

How to communicate on invasive alien plants? Effective involvement of stakeholders in 

addressing IAPs, Chaired by Ms Elisabete Marchante………………….……………………..37 

Biofuel crops in the Mediterranean: exploring the use of risk species, Chaired by Mr Pierre Ehret 

and Mr Roberto Crosti………………………..…………………………………………………….38 

Section 4: Management of invasive alien plants 

Field Trip: hands on survey for alien weeds, Chaired by Mr Giuseppe Brundu and Mr Necmi 

Aksoy…………………………………………………………………………………….…………….40 

Building a network for the control of Ambrosia artemisiifolia in the Mediterranean, Chaired by 

Mr Christian Bohren……………………………….……………………………………………….42 

Measures preventing the introduction of invasive plants in arable crops, Chaired by Ms Garifalia 

Economou and Mr Ahmet Uludag………………………………………………………..……….44 

11

Oral contributions 

Opening speeches 

The impacts of global change on plant life in the Mediterranean region and the spread of invasive 

species, Prof. Vernon Heywood, UK………………………………………………………..…….48 

Flora of Turkey: Richness, updates, threats, Mr Necmi Aksoy, Turkey (Abstract)…………..….64 

Role of soil communities and novel weapons in exotic plant invasion: an update, 

Prof. Inderjit, India……………………………………………..………………………………..….65 

Invasive Weeds threats in Gangetic inceptisols of India, 

Prof. Ratikanta Ghosh, India………………………………………………………………...…….71 

Niche modeling in invasive plants: new insights to predict their potential distribution in the 

invaded areas, Prof. Ramiro Bustamente, PC Guerrero, FT Peña-Gómez, Chile…….…...77 

Bern Convention on invasive alien plants, the Code of conduct on horticulture and invasive alien 

plants, Mr Eladio Fernandez-Galiano, Council of Europe (Abstract)………..………..…89 

EPPO activities on Invasive Alien Plants, Ms Sarah Brunel, EPPO (Abstract) …………..……90 

Role of the European Food Safety Authority in risk assessment of invasive species potentially 

harmful to plants, Ms Sara Tramontini, V. Kertesz1, E. Ceglarska1, M. Navajas, G. Gilioli, 

EFSA (Abstract) ………..………………………………………………..…………..……91 

Exploring options for an early warning and information system for invasive alien species in 

Europe, Mr Riccardo Scalera, P Genovesi, IUCN………………………………..…..……92 

European Environment Agency: Activities addressing invasive alien species, 

Mr Ahmet Uludag, EEA (Abstract)....................................................................................105 

Results of the survey on invasive alien plants in Mediterranean countries, Mr Giuseppe Brundu, 

Italy, Mr Guillaume Fried, France, Ms Sarah Brunel, EPPO. (Abstract)………………106 

12

Section 1: Plant invasions in the Mediterranean: where do we stand? 

Chair: Prof Vernon Heywood 

Molecular research as tool for managing biological invasions: Acacia saligna as a case study, 

Ms Geneviève Thompson, JJ Le Roux, DU Bellstedt, DM Richardson, JRU Wilson, South 

Africa………………………………………………………………………………………..….…...107 

Prioritization of potential invasive alien species in France, 

Mr Guillaume Fried, France………………………………………………….………………….120 

Modeling range changes of invasive alien and native expanding plant species in Armenia, 

Mr George Fayvush, Kamilla Tamanyan, Armenia………..……….…………………….139 

Noxious and invasive weeds in Greece: current status and legislation, 

Mr Petros Lolas, Greece……………………………………………..…………...………148 

A tales of two islands: comparison between the exotic flora of Corsica and Sardinia, Mr Daniel 

Jeanmonod, Switzerland, and Mr Giuseppe Brundu, Italy (Abstract)………..….………155 

New species threatening the biodiversity in Morocco: Verbesena encelioides (Asteraceae), 

Prof Abdelkader Taleb, M Bouhache & B El Mfadi, Morocco………………………...…156 

Section 2: Early warning 

Chair : Mr Ahmet Uludag 

Stages in the Development of an Early Detection and Rapid Response (EDRR) Program for 

Invasive Alien Plants in California, Mr Kassim Al-Khatib, Joseph M. DiTomas, USA….168 

Early experiences in the establishment of a National Early Detection and Rapid Response 

Programme for South Africa, Mr Philip Ivey, John Wilson, Ingrid Nänni1 and Ms Hilary 

Geber, South Africa………..…………………………………………………...……....…175 

The NOBANIS gateway on invasive alien species and the development of a European Early 

Warning and Rapid Response System, Ms Melanie Josefsson, Sweden (Abstract)…..…192 

From mediocrity to notoriety - the case of invasive weedy rice (Oryza sativa) biotypes in 

Malaysian rice granaries, Mr Baki Bakar, Malaysia………..……………………….……193 

Assessment and attempted eradication of Australian acacias in South Africa as part of an EDRR 

programme, Mr John Wilson, Haylee Kaplan, Carlo de Kock, Dickson Mazibuiko, Jason de 

Smidt, Rafael D. Zenni, Ernita van Wyk, South Africa………………….………..………206 

The value of context in early detection and rapid response decisions: Melaleuca invasions in 

South Africa, Mr Ernita Van Wyck, Llewellyn Jacobs and John Wilson, South Africa…..213 

13


Chair: Prof. Ramiro Bustamente 

Code of conduct on horticulture and invasive alien plants, 

Prof. Vernon Heywood, UK (Abstract) ………………………………………….………224 

Industry view on importance and advantages of a Code of Conduct on horticulture and invasive 

alien plants, Mr Anil Yilmaz, Turkey (Abstract) ………..………………………….……225 

Effectiveness of policies and strategies in tackling the impacts on Invasive Alien Species on 

biodiverse Mediterranean ecosystems in southwest Australia, 

Ms Judy Fisher, Australia (Abstract) ………………………………………...…………226 

Combining methodologies to increase public awareness about invasive alien plants in Portugal, 

Ms Elisabete Marchante, HMarchante, M Morais and H Freitas, Portugal………….…227 

Outcomes of the Tunisian Experience on Farmer Field School Management of an invasive 

species Solanum elaeagnifolium, Mr Mounir Mekki, M. M’hafdhi, R. Belhaj and K. 

Alrouechdi, Tunisia………..…………………………………………………………...…240 

Legislative, biological and agronomic measures to comply with the Bern Convention recommendation 

n141/2009 on "Potentially invasive alien plants being used as biofuel crops" by Contracting Parties 

in the Mediterranean Basin, Mr Roberto Crosti, Italy (Abstract) ………..…..……………249 

Biomass crops in the Mediterranean: can experiments in Languedoc Roussillon help characterize 

the risk of invasiveness of the plants used? Mr Pierre Ehret, France……............………250 


Chair: Mr Giuseppe Brundu 

Management of alien plant invasions: the role of restoration - Insights from South Africa, Ms 

Mirijam Gaertner, Patricia M. Holmes & Mr Dave M Richardson, South Africa…….…256 

A large-scale project of invasive plant coenosis control in Mediterranean sand coastal area: two 

case studies and a model to standardize the management criteria, 

Mr Antonio Perfetti, Italy (Abstract) ……………………………………...………….…267 

Three tools to manage alien weeds in Swiss agricultural and non agricultural environments - a 

proposal, Mr Christian Bohren, Switzerland………………………………..……………268 

Biology and control of the invasive weed Heterotheca subaxillaris (camphorweed), 

Ms Mildred Quaye, Tuvia Yaacoby and Baruch Rubin, Israel…………………...………274 

Mesquite (Prosopis juliflora): A threat to agriculture and pastoralism in Sudan, 

Mr Abdel Gabar T Babiker, Nagat EM and Ahmed EAM, Sudan…………..……………283 

Is bio control of Ambrosia spp. with Epiblema strenuana found in Israel possible? 

Mr Tuvia Yaacoby, Israel (Abstract)………..…………………………………..…….…288 

14

Posters 

Section 1: Plant invasions in the Mediterranean: where do we stand? 

Inventories of invasive alien plants in Mediterranean countries 

Lists of invasive alien plants (IAPs) as a key issue/tool in effective management of invasive nonnative 

species, Mr Pavol Eliáš, Slovakia……..………...…………………………..….…290 

Monitoring Invasive Alien Plants in the Western Black Sea Region of Turkey, 

Mr Necmi Aksoy, Ayşe Kaplan, Neval Güneş Özkan , Serdar Aslan , Turkey………...….304 

Alien Plant Species in the Western Part of Turkey: Assessing their Invasive Status 

Mr Emin Ugurlu, Turkey & Mr Roberto Crosti, Italy (Abstract)……………………......309 

Invasive plants in Armenia (current situation), 

Ms Kamilla Tamanyan & George Fayvush, Armenia……………………………….....…310 

Invasive aquatic plants in the French Mediterranean area, 

Ms Emilie Mazaubert, Mr Alain Dutartre, Nicolas Poulet, France………...……………316 

The inventory of the alien flora of Crete (Greece), Ms Costanza Dal Cin D’Agata, Greece, Ms 

Melpomene Skoula, Greece & Mr Giuseppe Brundu, Italy (Abstract)…………………..325 

Cactaceae naturalized in the Italian Mediterranean region 

Mr Alessandro Guiggi & Mr Giuseppe Brundu, Italy (Abstract)…………...........……...326 

Comparison of the alien vascular flora in continental islands: Sardinia (Italy) and Balearic Islands 

(Spain), Ms Lina Podda, Italy (Abstract)………………………………………………..327 

Is it the analogue nature of species which enables their successful invasion in woodland and 

coastal ecosystems of the southwest Australian Mediterranean biodiversity hotspot? Ms 

Judith L. Fisher, D Merritt & K Dixon, Australia (Abstract)……………………..……..328 

Inventories of weeds in Mediterranean countries 

Alien plants in cotton fields and their impact on Flora in Turkey, Mr İlhan Üremiş, Bekir Bükün, 

Hüseyin Zengin, Ayşe Yazlik, Ahmet Uludağ, Turkey (Abstract)………………….…….329 

Some Invasive Weeds in Turkey: Diplachnea fusca, Chondrilla juncea, Bromus spp., Mr 

Demirci, M., Ilhan Kaya, H. Aykul, S. Türkseven, Y. Nemli, Turkey 

(Abstract)…………………………………………………….…………………….…….330 

Some Important Invasive Plants Belonging to the Asteraceae Family in Turkey, Ms Ilhan Kaya, I. 

Tepe, R. Yergin, Turkey (Abstract)………………………………………………....……331 

Some Invasive Obligate Parasitic Plants: Cuscuta spp., Orobanche spp., Phelipanche spp., Mr 

Yildiz Nemli, R. Yergin, Ş. Tamer, P. Molai, A. Uludag, Turkey…………………..……..332 

Some invasive weeds in cereal areas of Northern Cyprus: Oxalis pes-caprae and Gladiolus 

italicus, A. Göksu, Y. Nemli, K. Vurana, B. Gökhan, S. Türkseven, M. Demirci, A. Erk, E. 

Hakel, Cyprus & Turkey (Abstract)…………………………………………….………..335 

15

Section 2: Early warning 

Validation and use of the Australian Weed Risk Assessment in Mediterranean Italy, Mr Roberto 

Crosti, Ms Carmela Cascone & Mr Salvatore Cipollaro, Italy (Abstract)……..........….336 

A proposal for a cooperation program on modeling the spread of invasive weeds, 

Mr Guillaume Fried, France, Mr Anwar Al Mouemar, Syria & Mr Henry Darmency, 

France (Abstract) ……………………………………………………….…...……...…...337 

Impact of Humulus japonicus on riparian communities in the south of France, 

Mr Guillaume Fried, France (Abstract) ………........................................................……...338 

Allelopathic effects of Oxalis pes-caprea on winter cereal crops, Mr Mohammed Bouhache, Prof. 

Adbelkader Taleb & M. A Gharmmate, Morocco………...…………….………………...339 

Fitness of the populations of invasive volunteer sunflower, Ms Sava Vrbnicanin, Ms Dragana 

Bozic, Ms Danijela Pavlovic & Ms Marija Saric, Serbia (Abstract) ………….....……...348 

Particular cases of invasive alien plants and weeds 

Nicotina glauca: an invasive alien with harmful potential, 

Mr Stephen L Jury & Mr JD Ross, UK (Abstract) ………...………………..…..…….....349 

Tree of heaven (Ailanthus altissima) – Establishment and invasion in Croatia, Mr Veljko Lodeta, 

Mr Nemad Novak & Mrs Maja Kravarscan, Croatia………...………………….…….....350 

Effect of Ambrosia artemisiifolia invasion on public health and agricultural production in 

Hungary, Ms Okumu Martha, É Lehoczky, Hungary………...…………………………...353 

Heracleum sosnovskyi habitats and naturalization in Lithuania, 

Ms Ligita Baležentienė, Lithuania………...............................................................……...366 

Distribution of silverleaf nightshade (Solanum elaeagnifolium) in Greece and invasiveness as 

related to leaf morphological characters, Ms Garifalia Economou, Ms Costas Fasseas, D. 

Christodoulakis & Ilias S. Travlos, Greece (Abstract) ………...…………………...…...373 

Germination ecology of the invasive Acacia saligna (Fabaceae): interpopulation variation and 

effects of temperature and salinity, 

F Meloni, CA Dettori, F Mascia, L Podda, G Bacchetta, Italy……………….......……...374 

Assessing the potential invasiveness of Cortaderia selloana in wetlands through seed 

germination study, Ms. Lina Podda, Italy (Abstract) ………................................……...386 

16


Industry view on importance and advantages of a Code of Conduct on horticulture and invasive 

alien plants, Mr Anil Yilmaz, Turkey (Abstract) ………...…...……………………..…...387 

Anigozanthos hybrids: what are the chances of eradicating this flower-farm escapee? 

Mr Ivey Philip, South Africa (Abstract) ……………………………………..…...……...388 

Use of ―native‖ Cardoon (Cynara cardunculus) as a bioenergy crop in the Mediterranean basin: 

concerns regarding invasive traits of some taxa, Mr Roberto Crosti, Italy, & Ms Janet A. 

Leak-Garcia US………...…………………………………………………………….…...389 


Management of invasive alien plants in Mediterranean countries 

Control experiments on selected invasive alien species in the Bulgarian flora, Mr Vladimir 

Vladimirov & Ms Senka Milanova, Bulgaria (Abstract) ………...……………………...392 

Management of Ludwigia peploides (water primrose) in the Vistre River (South-East of France): 

first results, 

Mr Alain Dutartre, Mr C. Pezeril, Ms Emilie Mazaubert, France (Abstract) ………......393 

A project for the eradication and the control of Ailanthus altissima in a river park in Northern 

Italy, Ms Anna Mazzoleni, Elena Tironi, Eric Spelta, Gianluca Agazzi, Federico Mangili, 

Gabriele Rinaldi, Italy………...……………………………………………………..…...394 

Solanum eleagnifolium, an increasing problem in Greece, Prof Eleni Kotoula-Syka, Greece....400 

Plant invasion, soil seed banks and native recruitment in two urban Mediterranean woodland 

remnants, in southwest Australia, Ms Judith L. Fisher, Australia & Mr Roberto Crosti, Italy 

(Abstract) ………...………………………………………….…………….………….....404 

Management and experiments of weeds in Mediterranean countries 

Applying cover crops to reduce impacts of Egyptian Broomrape in infested fields, Ms Mitra 

Ghotbi, Ms Marjan. Ghotbi, Iran, Ahmet Uludag, Turkey………..............................…...405 

Biological characteristics of Giant sumpweed seed (Iva xanthifolia) and the possibilities for 

fighting it by using soil herbicides, Ms Dragana Marisavljevic,Mr Branko Konstantinovic, 

Ms Danijela Pavlovic, Ms Maja Meseldzija, Serbia………...……………..……………..409 

Allelopathic potential of rice (Oryza sativa) cultivars on barnyard grass (Echinochloa crus-galli), 

Ms Leila Jafari, Mr Hossein Ghadiri & Mr Ali Moradshahi, Iran…………….....………416 

Biological control 

Solanum elaeagnifolium, an emerging invasive alien weed in the Mediterranean region and 

Northern Africa, Mr Javid Kashefi, Greece (Abstract) ………......................……...…...429 

Evaluation of Indigenous Fungi as Potential Biological Control agents to Cocklebur (Xanthium 

strumarium), Ms Alloub Hala, TT Abdeldaim, Sudan….…………….………..…….…...430 

17

Presentation of the Thematic Workshops 


2 nd Workshop on Invasive alien plants in Mediterranean type regions of the world 

19

Thematic Workshop Session 1.1 

Using the prioritization process for Mediterranean countries 

Chaired by Mr Guillaume Fried (fried@supagro.inra.fr) and Ms Sarah Brunel (sb@eppo.fr) 

Description of the project 

The European and Mediterranean Plant Protection Organization is in the process of developing a 

prioritization process for invasive alien plants which aims: 

- to produce a list of invasive alien plants that are established or could potentially establish 

in the EPPO region; 

- to determine which of these invasive alien plants have the highest priority for an EPPO 

pest risk analysis. 

This process consists of assessing plants through simple and transparent criteria such as the 

spread potential of the plant, the potential negative impact of the plant on native species, habitats 

and ecosystems, etc. This process is currently under use and testing in France and in Belgium. It 

is being implemented through workshops where experts bring their results for specific plants, 

and compare and discuss these. Such a tool eases the dialogue among experts and the 

homogenisation of definitions, and allows lists of invasive alien plants to be drafted giving 

priority at a regional scale. This could be done at the scale of the Mediterranean area. 

Aims of the thematic workshop 

- to make the prioritization process known 

- to test the process for the 5 following invasive alien plants relevant to the Mediterranean 

area: Cortaderia selloana (Poaceae), Solanum elaeagnifolium (Solanaceae), Ludwigia 

grandiflora & L. peploides (Onagraceae) and Fallopia baldschuanica (Polygonaceae). 

Tasks for the coordinators prior to the workshop 

- the document describing the prioritization process will be sent to the participants of the 

thematic workshop 

Tasks for the participants prior to the workshop 

- participants would have read the documents sent prior attending 

- the participants would have gathered information and run the process for the 5 species to 

be tested: Cortaderia selloana (Poaceae), Solanum elaeagnifolium (Solanaceae), Ludwigia 

grandiflora & L. peploides (Onagraceae) and Fallopia baldschuanica (Polygonaceae). 

Links with other thematic workshops 

This process will be presented during an oral presentation in session 1 by Guillaume Fried. 

General work on lists of plants for the Mediterranean would have been presented in the opening 

speeches by Giuseppe Brundu, Guillaume Fried and Sarah Brunel. 

The thematic workshops on eradication and early warning could take the prioritization process 

into account in their discussions. 



20

Conclusions of the thematic workshop 

Mr Fried went through the process with the case of Cortaderia selloana. The process raised 

questions: 

- on the potential impact of the species: shall species which are reservoir (i.e., host or vector 

for diseases, pathogens) be ranked higher? 

- on the spread of the species: shall planting for ornamental purposes be considered as an 

element to be taken into account in the spread potential of a species? 

- on the final use of the process in building lists and 

- on the audience targeted by the process. 

The group was concerned that a prioritization process should be as simple as possible so as to 

make fast assessments. 

The possibility to develop a tool that could be used by both the ministries of environment and 

agriculture was raised, and this should be attempted as much as possible as both ministries are 

trying to develop partnerships within EPPO countries. 

In general, the group concluded that the prioritization process is useful and feels a gap. Countries 

are willing to use it and to adapt it to their national peculiarity. It appeared that the experience in 

California is similar, setting criteria that need to be answered on a scale of 0 to 5. 

Experts from South Africa, Morocco, Tunisia, and Armenia wanted to be involved in the ongoing 

EPPO work on the prioritization process, and to test the process for the list of invasive alien 

plants recorded for their countries. 

The article on the prioritization process to be published in the EPPO bulletin will be circulated to 

the participants of the workshop. 



21

Thematic workshop Session 1.2 

Alien trees in the Mediterranean countries: focussing on Acacia spp. 

Chaired by Ms Genevieve Thomson (gen@sun.ac.za) and Mr Giuseppe Brundu (gbrundu@tin.it) 

Description of the target species 

Many species of the genus Acacia have been voluntarily introduced by humans in numerous 

Mediterranean Type Regions of the World, mainly as silvicultural and ornamental species. There 

are however, many other uses including the stabilisation of sand dunes and land reclamation; the 

use as a livestock fodder, for leather tanning and fuel; as a medicine, paint or perfume. For 

instance, Acacia spp. are grown in the USA for sale as cut flowers. Acacia dealbata is a popular 

plant in Europe and has been grown in Southern France and Italy (since 1918), and sold as a cut 

flower under the local common name ―Mimosa‖. A. baileyana purpurea is also grown in Israel 

for its cut foliage. Today, products from a number of Acacia species are utilised commercially in 

Australia and throughout the world. The timber of A. melanoxylon is highly valued for building 

and furniture making, while lower quality timbers from other species have been used for fence 

construction. Plantations of fast growing Australian Acacia species are being planted in 

developing countries as a source of firewood, where population growth has led to the depletion 

of the native tree species which were traditionally used as a fuel source. More recently, Acacia is 

also being considered as a biomass producer in short rotation coppice systems. As with other 

invasive alien plants of the legume family, the success of many Acacia species outside their 

native ranges has been attributed to their ability to fix nitrogen, their tolerance to fire, high seed 

production, and allelopathic effects. Some of these traits are also responsible for rendering the 

eradication/control of acacias more problematic. 


The scope of the workshop is to raise awareness on species within the Acacia genus in all 

Mediterranean Type Regions of the World; as well as to compile an inventory of all the 

introduced/naturalised species. Furthermore, the workshop aims to build a network of interested 

people/stakeholders for further research activities/projects and to prevent the un-regulated entry 

and spread of these species through common actions across the respective regions. 


Prepare a general list of Acacia species cultivated/naturalised in the Mediterranean Type Regions 

of the World with main cultivation purposes/introduction pathways. 


Collect information on Acacia species concerning their own country/region (species, sub-species 

or hybrids, pathways, distribution, threats, legislation, programme for eradication/control etc.) 

prior to attending. 



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- General work on lists of plants for the Mediterranean. 

- Thematic workshops on eradication, early warning and the prioritization process should 

consider this thematic workshop in their discussions. 


Fifteen people from 10 Countries (Chile, Croatia, France, Israel, Italy, Kenya, Malaysia, 

Portugal, South Africa, United Kingdom) took part to the workshop on Acacia spp. 

At the beginning of the workshop the background idea was presented as well as main research 

activities that are on-going in South Africa (which was also the subject of a general oral 

presentation). 

All participants then briefly presented their country situation with concern to main introduction 

pathways and purposes for Acacia spp., the most common species introduced, problems and 

impacts, activities for control and general perception of the status of these species in their 

countries. 

From the general discussion, more evidence was raised on the fact that many species of this 

genus have been voluntary introduced by man outside their native range, for many different 

purposes, and that many of them are naturalised to invasive elsewhere. 

In some cases the species are environmental weeds, and there is quite a lot of evidence of the 

general difficulties in control (in relation to plant main traits, such as resilience to fires, high seed 

production, seed hardiness, capability of vegetative spread), even if, for some species, biological 

control is already available. 

In spite of the invasiveness and/or of the potential risks, there are quite high diverse perceptions 

between relevant stakeholders in different countries. In some cases, local forestry politics and 

land managers seem not to be aware of potential risks, and still promote the introduction of the 

species, even at large scale plantations, as these species are among the few capable of growing in 

very dry or in highly degrade sites. 

Therefore, in spite of large removal interventions, e.g. those taking place in Portugal sand dunes 

(where different removal/control techniques are also under evaluation – including the review of 

the national legislation), or in Israel, in other countries Acacia spp. are broadly planted and 

introduced in novel habitats, e.g. for soil erosion, road side stabilisation, goat fodder, such as in 

Chile or in Kenya, or as ornamental (A. dealbata in France). In other countries, both new 

introductions and control activities are occuring. Furthermore, there is a general interest for new 

plantings of Acacia saligna for biomass production, in short rotation forest systems, e.g. in the 

south of Italy (where it is already described ad highly invasive in natural and semi natural 

habitats and as a strong coloniser of burned soils). A general oral workshop presentation 

addressed the problem of biofuels (on the 04/08) with reference to this problem. It is noteworthy 

that in Malaysia, where A. mangiun was introduced as a forestry species, there is now a general 

perception of it as a weed, also because production incomes are not as relevant as expected. 

Although not all expected outcomes of this thematic workshop were achieved, the general 

discussion was very useful to exchange knowledge on these species, and general information of 

species presence and status in different countries, and participants agreed to provide further 

country information for updating the list of Acacias species traded/planted/naturalised/invasive 

in the Mediterranean. So far, the list includes, e.g., A. cyclops A. dealbata, A. karoo, A. 

longifolia, A. mearnsii, A. melanoxylon, A. pycnantha, A. retinoides, A. saligna. 



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Similarities and differences between distribution of invasive alien plants in the Black Sea 

and Mediterranean area 

Chaired by Mr Necmi Aksoy (necmiaksoy@duzce.edu.tr) 


The main goal of this project is to evaluate the similarities and differences between the 

distribution of invasive plants in the Black Sea and in the Mediterranean Area, and in particular: 

- to understand the components of the Mediterranean Flora and the Euro-Siberian Flora in 

the Black Sea area; 

- to list the invasive alien plants common to the Black Sea and the Mediterranean areas; 

- to list the differences in invasive alien plants in the Black Sea and the Mediterranean 

areas; 

- to compare which of these plants pose the highest risk of invading the Black Sea and 

Mediterranean areas; 

- to observe the invasive characteristic of alien plants in the Black Sea and in the 

Mediterranean areas. 

The workshop consists of observing and identifying plants through their invasive characteristics 

through criteria such as the spread potential of the plants, their potential negative impacts on the 

native species, habitats and ecosystems in the Black Sea and Mediterranean areas. We may also 

develop new means to observe and compare the invasive plants of both regions. Through 

understanding the invasive plants in the Black Sea area wewill discuss and test whether it is 

possible to transfer the methods which are being implemented in the Mediterranean area. 


- to define the differences and similarities of the alien plants in the Black Sea and the 

Mediterranean areas; 

- to make a list of the priority invasive alien plants in the Black Sea area; 

- to monitor some invasive alien species of the Black Sea area during the field trip of the 

workshop; 

- to consider methods to control the invasive plants in the Black Sea area. 

Tasks of the coordinator of the workshop 

- to send a document describing the Mediterranean Flora in the Mediterranean area and the 

Euro-Siberian Flora in the Black Sea area to the participants of the thematic workshop 

prior to the workshop; 

- to show some of the alien plants to the participants of the workshop during the field 

excursion. 


- participants are advised to read the document prior to attending; 

- they are also advised to make the necessary preparations for the field excursion. 



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This thematic workshop is particularly linked with the field trip. 


The following invasive alien plants common to the Black Sea and the Mediterranean areas were 

listed: Abutilon theuphrasti, Phytolacca americana, Opuntia ficus-indica, Agave americana, 

Amorpha fruticosa. 

Similarities and differences between the Mediterranean and the Black Sea Region were 

discussed. Historical patway must be follow in two areass are important elements to understand 

plant colonization and need to be considered. 

The participants dicussed to observe the invasive characteristics of alien plants in the Black Sea 

and in the Mediterranean areas. They considered that the number of species per square meter, 

area size, and observations must be done every year. 

The participants also elaborated a list of the priority invasive alien plants in the Black sea area: 

1. Abutilon teophrasti 

2. Phytolacca americana 

3. Opuntia ficus-indica 

4. Agave americana 

5. Solanum eleagnifolium 

6. Robinia pseudoacacia 

7. Eucalyptus camuldulensis 

8. Conyza canadensis 

9. Ambrosia elatior 

10. Xanthium spinosum were listed 

The following suggestions to control invasive plants in Black Sea area were made: 

- To consider models developed by other countries 

- To collaborate with the ministry of agriculture 

- To collaborate with the European Union 

- To build a network of universities 



25


Building an Early Detection Rapid Response (EDRR) for the Mediterranean 

Chaired by Mr Kassim Al-Khatib (kalkhatib@ucdavis.edu) and Mr Ahmet Uludag 

(ahuludag@yahoo.com) 


Early detection of invasive alien plants and quick coordinated responses are needed to eradicate 

or contain invasive plants before they become widespread and control becomes practically 

and/or financially difficult. Although early detection and rapid response are important elements 

of invasive plant management, currently there is no comprehensive regional system for 

detecting, and monitoring invasions of alien plants in the Mediterranean region. 

The group will discuss the existing EDRR in different locations of the region. EDRR system 

may exist in certain locations; however, inadequate planning and technologies, insufficient 

resources and information hindered EDRR efforts in other locations. 

The workgroup will discuss ways to develop plan to coordinate efforts and improve networking 

for the purpose of developing regional detection system. 


- To determine critical needs and resources to develop regional EDRR 

- To develop and priorities species lists for EDRR 

- To allow access to reliable, effective, and affordable invasive plants management 

information 

- To facilitate rapid and accurate species identification 

- To establish procedure for rapid risk assessment 

- To discuss mechanisms for coordinating the efforts of regional agencies and authorities to 

address EDRR. 


- Participants would have read this document prior attending 

- Prepare a short report on existing EDRR in your location 

- What is the preferred EDRR system for your location 

- Develop a vision of how you can contribute to a regional approach of EDRR and what are 

the limitations. 

Links with other thematic workshops and presentations 

- Related information will be presented and discussed in different session. Presentations of 

particular interest are: 

- Similarities and differences between distribution of invasive alien plants in the Black Sea 

area and Mediterranean area, Chaired by Mr Necmi Aksoy 

- Using the prioritization process for Mediterranean countries, Chaired by Mr Guillaume 

Fried and Ms Sarah Brunel 



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- Effectiveness of policies and strategies in tackling the impacts on Invasive Alien Species 

on biodiversity in Mediterranean ecosystems in South-West Australia, Ms Judy Fisher, 

Australia 

Conclusions of the workshop 

Participants from 11 countries participated, including Armenia, Bulgaria, France, Greece, 

Malaysia, Slovakia, South Africa, Sweden, Portugal, Turkey, USA. 

Early detection of invasive alien plants and quick coordinated responses are needed to eradicate 

or contain invasive plants before they become widespread and control becomes practically 

and/or financially difficult. Although early detection and rapid response are important elements 

of invasive plants management, currently there is no comprehensive regional system for 

detecting and monitoring invasions of alien plants in the Mediterranean region. 

The work group has discussed the existing Eealy Detection and Rapid Response (EDRR) in 

different locations, limitation to EDRR in the region, coordination and cooperation between 

locations, and resources needed for EDRR. Below is the summary and conclusions from the 

workshop discussion. 

Current Status of EDRR 

Inventories of invasive species 

- Slovakia has lists of invasive species and animals 

- Sweden has started the elaboration of a blacklist 

- Portugal has a list of species that must not be introduced. 

- France through the Botanical Conservatory networks have good lists of all plants including 

invasive species 

Political will needs to be strengthened 

- EEA, EPPO and the European Commissionare are considering the development of an 

EDRR 

- Currently, there are 2 desk officers working on invasive alien species at DG-Environment 

in Bruseels. 

- Member States are encouraging the European Commission to act on invasive alien species. 

Local legislation in place 

- Slovakia has law to offer protection of native composition of ecosystems to prevent the 

spread of invasive species. 

- Portugal has law forbidding sale of certain species 

Some local support from Nurseries that have sympathy for the problem 

- In Bulgaria, some nurseries have removed invasive alien plants from their stock and selling 

lists. Nursery champions need to be encouraged. 

Needs to Build EDRR 

Strengthen and encourage political will into actions and regulations 

- Resolve the issue of free trade versus environmental protection. Commission needs 

guidance; the stakeholders meeting in September 2010 will assist. 

- The European Commission needs to provide laws to allow countries to take legal action 

without fear of losing the challenge. 



27

- Member countries need to be able to monitor plants being imported by other member 

countries and be able to prevent import of potentially invasive species (perception that the 

Netherlands is the major importer of live plant material which is then distributed across the 

continent, but other states may be responsible too, Turkey has 6-8 major plant importers). 

- If regulations are imposed then means are needed to enforce them 

Need to strengthen law enforcement 

- In Portugal, species are meant to go through an impact assessment to clear species to enter 

the country, however, many species enter illegally by passing the impact assessment 

- Plants are grown illegally, misidentified and mislabeled 

Create awareness 

- policy makers – target them and train them – e.g. perception that Armenia is mountainous 

and therefore not subject to this invasion in reality 3% of land surface is already invaded 

by invasive plants 

- nursery industry 

- members of the gardening public 

- school children – Portugal have some very good examples and projects 

Establish local early warning system 

- Slovakia has no early warning system, as a result this type of scenario develops: inspectors 

in regions monitor the occurrence of invasive plants, they prepare a report on the 

elimination of particular species, no action is taken and since the report, the number of 

localities have increased five times and costs have increased five times as well. 

- In Portugal there is no early warning system in place. Researchers have applied for 

funding for such an early detection system but Nature Conservation has no plans to do this. 

- France has an early detection system working with all the environmental space managers 

and existing agriculture networks. 

Taxonomists need to be involved 

- to assist with development of inventories 

- training of new taxonomists to take over from retiring taxonomists 

An early warning email listserve e.g. google group could be created. 



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Identifying targets for eradication in the Mediterranean and eradication experiences 

Chaired by Mr Eladio Fernandez Galiano (Eladio.FERNANDEZ-GALIANO@coe.int) 


While eradications are considered a very efficient technique to manage invasive alien species, 

very few have been undertaken for plants in European and Mediterranean countries. One of the 

difficulties of such a task lies in the identification of those species that are still of limited 

distribution, but have the potential to have deleterious impacts and to spread further. The 

practical application of eradication, although being inexpensive and very cost effective if taken 

at an early stage, needs to be promoted through concrete cases. The Council of Europe has 

published a recommendation (no. 126 in 2004) of examples of invasive alien plants to be 

eradicated (see appendix below), and aims to help countries implement such action. The Council 

of Europe will work with its Member states to in the coming years to develop projects of 

eradication of invasive alien plants 


- to identify 5 or 6 invasive alien plants in Mediterranean countries that represent good 

targets for eradication; 

- for each of the cases, to clarify the stakeholders involved, the technique(s) to be used, the 

material and personnel needed, the budget, and communication methods; 

- to identify international expertise to be associated with each eradication case. 


- Participants should identify possible cases of eradication in their own country; 

- Participants should document each potential case of eradication (situation, stakeholders, 

method to be used, budget, communication, etc.). 


- the thematic workshops on the prioritization process (1.1), on EDRR (2.1) and on early 

warning in North-African countries (2.3) might highlight species that would be suitable for 

eradication. 

Concusions of the thematic workshop 

- Eradication and control of spread of invasive species are costly exercises. So much attention 

should be devoted both to their careful planning, long-term development and the choice of 

species to be controlled or eradicated. 

- There are already good methods to choose candidate species for eradication/control using 

criteria such as invasiveness, degree of impact on natural habitats or native species and 

present distribution (which can influence success of eradication). 

- Biological control should be systematically explored for invasive plants that are well spread 

and for which mechanical or chemical control are prohibited. 



29

- Eradication should be integrated in a much wider context of management and generally not 

used as a separate tool. 

- Eradication in the early stages of invasion should be a priority, which speaks strongly in 

favor of the establishment of an early-warning rapid response system. 

- Many eradications are a success and there is an urgent need to better document 

eradication/control operations, both those that are successful and those that are not and so 

often unreported. 

- Eradication/control plans should integrate a strategy for re-vegetation or ecological 

restoration of areas left base by removal of the invasive species. 

- While most eradications focus on a target species, more attention needs to be given to an 

―ecosystem approach‖, controlling one or several invasive alien plants in a particularly 

vulnerable ecosystem (eg. Dunes wetlands). 

- Eradication should be promoted for newly arrived species even if there are uncertainties on 

their invasiveness, applying the precautionary approach. 

Appendix 

The species listed in the recommendation 126 of the Council of Europe for which eradication or 

containment is recommended in Mediterranean countries are: 

Species Ecosystems Countries in which the 

species occurs 

Hydrocotyle ranunculoides Uncultivated Belgium, France, Germany, 

Italy, the Netherlands, 

Portugal, Spain, the United 

Kingdom. Italy, Palestine, 

Israel. 

Pueraria lobata Uncultivated Italy, Switzerland. 

Solanum elaeagnifolium Uncultivated and cultivated Algeria, Croatia, Cyprus, 

Egypt, France, Greece, 

Israel, Italy, ―the former 

Yugoslav Republic of 

Macedonia, Moldova, 

Montenegro, Morocco, 

Serbia, Spain, Syria, 

Tunisia. 



30

Other examples of species that have high capacity of spread and potentially high impacts: 

Species Ecosystems Countries in which the 

species occurs 

Araujia sericifera Uncultivated Spain, France 

Bothriochloa barbinodis Uncultivated and cultivated France 

Cenchrus incertus Uncultivated and cultivated Spain, Italy, Romania 

Cotula coronopifolia Uncultivated Portugal, Spain, Italy 

Eichhornia crassipes Uncultivated Portugal, Spain 

Fallopia baldschuanica Uncultivated Czech Republic, Spain, 

Italy, Slovenia, France, UK 

Hakea salicifolia Uncultivated Portugal 

Hakea sericea Uncultivated Portugal, France 

Myriophyllum 

Uncultivated Spain, Germany 

heterophyllum 

Pistia stratiotes Uncultivated Spain 

Senecio deltoideus Uncultivated France 

Sesbania punicea Uncultivated Italy 



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Cooperation/inclusion of North African Countries in European early warning system 

Chaired by Mr Mohamed Bouhache (m.bouhache@gmail.com) and Mr Riccardo Scalera 

(riccardo.scalera@alice.it) 

Why cooperation/inclusion? 

Biological invasions of alien plants and their pests do not only threaten biodiversity of concerned 

regions. They also affect the well-being and economies of human populations, endangering 

ecosystems and transforming landscapes. The movement of people and goods in the 

Mediterranean basin has favoured biological invasions in the regions since early times in human 

history. Today, since trade and tourism activities are very developed between Europe and North 

Africa, opportunities to exchange invasive alien species continue to be very high. Thus, our 

regions need to establish or to share an early warning framework and information system in 

order to be able to detect and react promptly to new invasions in order to respond to their 

ecological and economic threats. This requirement also complies with one recommendation of 

the European Strategy on Invasive Alien Specie adopted by the Council of Europe, which 

supports the development of effective systems to share IAS information with neighboring 

countries, trading partners and regions with similar ecosystems. While the European early 

warning strategies are in the course of being developed at both the EU level and at the level of 

single countries (e.g. Ireland) and regional networks (i.e. NOBANIS), the early warning and 

information system capacities of North African counties are still very limited. 


- to make the European early warning system known to North African countries; 

- to include (or cooperate with) North African countries in European early warning system; 

- to define the scope and objectives of the cooperative actions; 

- to share concepts and terminology; 

- to identify countries and/or authorities concerned in North Africa. 


- the document describing the European early warning system will be sent to the participants 

of the thematic workshop. 


- participants would have read the document prior attending 

- develop ideas on how to launch this cooperation or inclusion. 

Links with other thematic workshops and sessions 

This workshop will be preceded by three oral presentations: 

- by Riccardo Scalera: Towards an early warning and information system for invasive alien 

species (IAS) threatening biodiversity in Europe (in opening speeches session); 

- by Kassim Al-Khatib: Stages in the Development of an Early Detection and Rapid 

Response (EDRR) Program for Invasive Plants (in session 2) 



32

- by Philip Ivey: Establishment of a National early detection and rapid response programme 

- some early lessons (in session 2). 

- The recommendations of the thematic workshop on the prioritization process may be taken 

into consideration in the early warning workshop progress. 

Conclusions of the workshop 

Four participants took part in the workshop, and the following countries were represented: 

Morocco, Tunisia and Italy. 

The movement of people and goods in the Mediterranean basin has favoured biological invasions 

in the regions since early times in human history. Opportunities to exchange invasive alien 

species continue to be very high in the region, given the increasing levels of trade and tourism 

activities between Europe and North Africa. For this reason, initiatives to start the development 

of a regional early warning and information system for alien species should be undertaken as 

soon as possible. This would increase the capacity of Mediterranean countries to detect and react 

promptly to new invasions so as to respond to their ecological and economic threats. 

European early warning strategies are in the course of being developed at both the EU level and 

at the level of single countries (e.g. Ireland) and through regional networks (i.e. NOBANIS), but 

are not yet being duly considered in North African countries. 

In order to encourage and support the establishment of an early warning and information system 

in North African countries, to be coordinated and intergrated to the European one which is being 

developed, it is reccomended that a regional workshop is organised at the earliest convenience, 

so as to target the key representatives of the national authorities and academics. Such a workshop 

should be also aimed at raising awareness on the issue and promoting the increase in knowledge 

in the North African countries, and particularly in Morocco, Tunisia, Mauritania, Lybia and 

Algeria. 

In the meantime, as preparatory measures needed to guarantee a succesful implementation of the 

workshop, the participants agreed to start collecting all material and documents which might be 

useful to analise the state of the art in the region (inventories of alien species, studies on 

ecological and economic impact, examples of best practices and case studies, etc.) and a 

comprehensive list of contacts of concerned people from public adminstrations (ministry of 

agriculture, ministry of environment, etc.), universities and the private sectors, so as to start 

networking activities and identifing potential participants for the planned workshop. 

Both representatives from North African countries (Morocco and Tunisia) agreed to organise this 

workshop in their country, provided that some financial contribution be guaranteed by 

international organisations such as EPPO, FAO, CoE, EEA, etc. 



33


Implementing Codes of conduct on horticulture and invasive alien plants for the 

Mediterranean 

Chaired by Prof. Vernon Heywood (vhheywood@btinternet.com) 

Context 

The Code of Conduct on Horticulture and Invasive Alien Plants is a joint initiative of the 

Council of Europe (CoE) and the European and Mediterranean Plant Protection Organization 

(EPPO). It is addressed to governments and the horticultural industry and trade – plant importers, 

commercial nurseries, municipal nurseries, garden centres, aquarists – and to those who play a 

role in deciding what species are grown in particular areas, such as landscape architects, 

municipal parks and gardens departments, recreation and leisure departments. Its aim is to help 

prevent the spread of alien invasive species already present in Europe and prevent the 

introduction of possible new plant invaders into Europe. The Code is voluntary and its 

effectiveness will depend on how far the horticultural industry and trade are willing to adopt the 

guidelines and good practices proposed in it. To achieve this, it is necessary to raise awareness 

on this topic among the professionals concerned. 

Aims of the workshop 

- to examine how far the Code is being implemented in the countries bordering the 

Mediterranean; 

- to determine the main types of problem encountered in implementing the Code; 

- to seek solutions to the problems identified or propose how they may be addressed; 

- to consider whether there are any special factors that might affect the relevance and 

implementation of the Code to Mediterranean countries; 

- to examine links with other European, regional and national initiatives which aim to 

control or prevent entry of new and emerging invasive plant species. 


- to familiarize themselves with the Code (it is available in English, French and Spanish); 

- to ascertain, as far as possible, the response to the Code in their country and prepare a short 

note summarizing this; 

- to find out if there are other national Codes of conduct that may be relevant to the 

CoE/EPPO Code and its implementation in the Mediterranean. 


Most of the other thematic workshops address issues that are relevant such as prioritization, 

identification of target species, early warning, control and eradication and the need for 

communication with stakeholders. 



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- Codes of conduct are a useful approach to deal with invasive alien plants but should not 

preclude governments to take a more restrictive, law-based approach if this is necessary to 

avoid the entry, release and spread of invasive alien plants. 

- Codes of conduct will only work if the industry (horticulture, agriculture, forestry) adopts 

them and not if they are simply given to them to apply. 

- While European Codes of conduct can serve as a source of inspiration for 

government/industry practice, it is fundamental that they are modulated to the problems, 

language and culture of each particular state or region, so that national, regional codes 

become the real operative tool. 

- The elaboration of national or regional codes of conduct should serve as an excellent way to 

foster dialogue with the industry and the public on IAS. 

- A particular effort should be done to make Codes of conduct better known and used by 

clients (of the horticultural industry, or forest industry) both private and institutional. 

- Codes of conduct are a good tool to publicise the problem of invasive alien species to a 

wider public. 



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How to communicate on IAP? Effective involvement of stakeholders in addressing IAPs 

Chaired by Ms Elisabete Marchante (elizabete.marchante@gmail.com) 

The control and management of widespread invasive alien plants (IAPs) is extremely difficult 

and costly. Therefore, the best way to deal with invasive alien species is to start by preventing 

their introduction. Because every person is a potential vector for species introduction, it is 

necessary to start by educating the different publics about the problem and the species involved. 

A well-informed public can then contribute to the prevention, early-detection and management 

of invasive alien species. This thematic workshop aims to explore ways how scientists and 

practitioners engage with the public. 


- to understand the importance of science communication on IAPs; 

- to discuss different approaches used to communicate on IAPs; 

- to discuss ways to assess success of communication on IAPs. 


- to select amongst the abstracts received from the participants 4 or 5 examples and 

suggestions to be presented and discussed during the thematic workshop. 


- Participants would have prepared and sent to the coordinator a small abstract about 

ways/strategies they use (or would like to test) to communicate on IAPs. 


The thematic workshops on eradication and early warning could take communication into 

account in their discussion. 

Conclusion of the thematic workshop 

Although communication on IAPs is essential to prevent, early-detect and manage IAPs, this is 

still lacking. 

A round table during the thematic workshop highlighted that in Mediterranean type regions, 

several activities or documents have been used to communicate and raise public awareness about 

IAPs by different countries, namely: Czech Republic, France, Italy (Sardinia), Portugal, 

Slovakia, South Africa, Turkey, etc. Strategies used include: leaflets and printed documents, 

dedicated days to provide information, web pages, scientific meetings and publications, etc. 

―Taking action on management‖ is also a good communication strategy. Specific legislation can 

be used to raise awareness, but if not properly publicized may not be effective by itself. 

The effectiveness of using leaflets and other paper documents to raise public awareness on IAPs 

is in general seldom measured. Although difficult to measure, evaluation is essential to 



36

sustainably use the available funding in approaches that will be most effective in changing 

attitudes. In Portugal, the evaluation of the effectiveness of the approaches used was initiated for 

some activities, which represents one of the leading experiences in Europe. From the Portuguese 

experience, it appears that in general, the use of leaflets is more effective if combined with a talk, 

or with some practical, hands-on, interactive activities/approaches. 

As stated by different participants, funding is insufficient and often a limitation in 

communication on IAPs. It was nevertheless mentioned that financial support for these activities 

can be included in the context of research and management projects or through specific 

measures, e.g., LIFE+ Information and Communication. Additionally, some communication 

approaches can focus on stimulating the different publics to promote actions themselves. 

Ideally, information about biological invasions and IAS should be included on school curricula, 

so as to start educating the new generations, who, in addition, are very important vectors of 

information. For that, it is necessary to start training the schoolteachers. However, 

communication on IAS cannot rely only on the younger generations, and has to target different 

publics and stakeholders: the horticultural industry, politicians, policy makers, scientists, 

municipalities, forestry associations, conservation managers, farmers, etc. Media should also be 

highly involved. 

The participants also concluded that strengthened collaborations, sharing experiences, successes 

and failures in communication is essential and should be sought after. In many countries much 

work has been done in communication, including non-Mediterranean countries, but information 

is often too scattered. Different websites and approaches used could be gathered in a common 

website aiming at aggregating much of the information available about communication on IAPs, 

and making it more easily available. 

It was also stressed during the workshop that communication strategies may need to be prepared 

with the collaboration of communication experts. An effort should be done to develop ways to 

measure the effectiveness of communication campaigns, i.e., publications, actions, etc. This can 

be achieved, at least partially, if part of the management budget is directed to the evaluation of 

the communication actions. 

As a result of this workshop, it is proposed to organize a ―Mediterranean wide Cleanup day‖, 

including hands-on activities to control/remove IAPs, which would be widely publicized, 

engaging the media and stakeholders. This could be organized simultaneously by countries of all 

Mediterranean regions of the world, and be planned for 2011 or 2012. 

Note: It should be kept in mind that participants in the thematic workshop may not be 

representative of their countries or regions, i.e., there are other communication and public 

awareness actions taking place elsewhere, as shown by other talks at the workshop (Switzerland, 

USA, other activities in Italy, etc.), and also many activities developed by non-participants 

entities/researchers and countries. 



37

Thematic workshop 3.3 

Biofuel crops in the Mediterranean: exploring the use of risk species 

Chaired by Mr Pierre Ehret (pierre.ehret@agriculture.gouv.fr) nd Mr Roberto Crosti 

(roberto.crosti@isprambiente.it) 

Increase demand for energy in the Mediterranean Regions enhanced the development of large 

scale biofuel cropping systems consisting of the use of plant biomass for energy production. 

Energy can be generated from ethanol, oil and combustion produced from plant material. In 

addition, recently, many businesses are investing in technologies (molecular genetics and 

engineering) to provide fuel from microalgae. 

To gain real environmental benefits, however, biofuel crops need to be farmed in an 

environmental sustainable manner. Major concerns include the loss of biodiversity, as a 

consequence of the potential escapes of aggressive crops cultivars which can compete, in the 

wild, with native vegetation. Several biofuel species or cultivars have traits in common with 

invasive species and may harm both the farmland biodiversity and functionality. Many of those 

potential biofuel crop species, selected for broad ecological amplitude, rapid growth, high seed 

production, vegetative spread, resistance to pests and diseases are, in fact, potentially invasive. 

Furthermore, in farmlands, habitat modification, distorted water balance and nutrient cycle, 

altered fire regimes and abandonment of arable lands might contribute to the establishment of 

invasive species in new or temporarily ―vacant niches‖. Planting massive quantities of vigorous 

plant varieties on a large scale by repeated introductions, often supported by economic subsidies, 

in different climates and soil conditions increases the propagules pressure and likelihood of 

―crop escape‖, with subsequent, establishment of new biological invaders. Many of the proposed 

biofuel crops in the Mediterranean basin are already considered invasive elsewhere. 

On the other hand, some biofuel crops may have showed less aggressive trends, but this kind of 

information might not be often published and would be useful to share. 

During the WS a presentation of the preliminary results of a survey on Short Rotation Coppicing 

species which under the EU common agricultural policy (CAP) are granted support payments 

(each member state defines the species). 

Aims of the workshop 

- To raise awareness of potential invasiveness of biofuel species; 

- To set up a network to monitor both ―field escapes‖ and ―legislative acts‖; 

- To verify if, in Mediterranean type Regions, escapes have already occurred and if native 

habitats have been harmed; 

- To share experience concerning monitoring systems of biofuel species. 


- registered participants will get, by e-mail, several papers on the topic; 

- to respond to the questionnaire. 


- the chairmen of the thematic workshop will circulate a questionnaire and several papers 

and aggregate the results to be presented during this thematic workshop. 



38


Posters and talks in the meetings (e.g. by the chairmen in the same day of the workshop). 

Conclusion of the thematic workshop 

The thematic workshop began with the presentation of the survey launched by Roberto Crosti on 

"tree species getting EU Common Agricultural policy‖. Nine (9) countries out of 27 UE member 

states had provided a response. 

The lists are related to an EU directive on the promotion of the use of energy from renewable 

sources (2009/28/EC) that is asking to produce a list of trees that can get the same kind of 

subsidies as annual or herbaceous perennials crops if planted as short rotation coppices. In some 

countries, several known invasive species are on such lists. 

Participants from the following countries presented their knowledge of the situation of species 

planted as biofuel crops in their countries: Australia, Bulgaria, Greece, Hungary, Iran, Israel, 

Turkey and Sudan. Besides Italy and France, having presented papers just before in the general 

session, none of the participants had activities in direct connection with the biofuel crop 

production sector. 

From the round table, it appeared that: 

- There is a lack of interest from relevant institutions toward the biofuel crop planted that 

will not be harvested and that produce high quantities of propagules. 

- farming systems in most of the places under Mediterranean climate are not well adapted to 

biofuel feedstock production (small plots, small scale farms) and are more subject to 

invasion due to the presence of perennial neighbouring crops and to the low distance 

between cultivated land and almost natural or unmanaged land. 

Information was exchanged about particular species: 

- Pauwlonia elongata: this "new" fast growing species might need attention even if it is 

promoted as non invasive. 

- Acacia saligna: a strong consensus among participants from countries where the species is 

invasive was reached to alert other countries on the danger of planting this species. 

From a rural development point of view, it was stressed that there is a need to support local 

activities based on land use in rural areas with Mediterranean climate. Indeed these areas are 

often less competitive for agriculture or livestock production than other regions (particularly in 

EU countries). The group wondered if biofuel crops represent a good choice, and concluded that 

some other solutions may be more suitable to local farming systems. 

As a summary: 

- Biofuel feedstock cultivation does definitively select alien plants that have many traits in 

common with invasive plants and has therefore to be closely evaluated and monitored. 

- Some species are already well known as costly and difficult to manage invasive plants, in 

particular Acacia saligna, and there is a strong consensus to recommend the ban of 

plantation of this species. 



39


Field Trip: hands on survey for alien weeds 

Chaired by Mr Giuseppe Brundu (gbrundu@tin.it) and Mr Necmi Aksoy 

(necmiaksoy@duzce.edu.tr) 

Description of the activity and related final workshop 

The idea behind the two-day field excursion is not only to visit remarkably interesting sites from 

the environmental and cultural point of view, but also locations that, so far, are poorly studied 

from the point of view of plant invasions and exotic floras and inventories, thus to collect useful 

information and eventually to write an excursion report or possibly a short paper that could 

represent a preliminary contribution towards the exotic flora of a larger area. Field activities will 

be discussed during a workshop. 

Aims of the activity 

During the two days of the excursion different sites will be visited. In each site, according to the 

number of participants, the group could be divided in 2-3 sub-groups, having the possibility to 

survey a larger area, taking photos, recording locations by GPS positioning and other relevant 

information or data, and collecting plant samples. 

Tasks for the coordinators prior the workshop 

It is advisable to collect as much available information as possible on the study area in advance. 

The local botanists will be in charge to provide local "grey" literature on (invasive) alien plants 

and copies of the Turkish flora (or parts of it) that could be used for plant identification (and 

possible other "botanical" tools for plant identification and collection tools, such as lenses, paper 

sheets etc.). 

Tasks for the participants during the field-trip and the workshop 

During the field trip it is advisable to assign specific task to each component of the group, even if 

the same task (e.g. making photographs) could be done by more than one person. Example of 

specific tasks are e.g., making photographs, taking notes, collecting specimens as herbarium 

samples, interviewing people, taking note, collecting GPS locations, etc. 

At the end of the field trip participants will be asked to share the collected data, photos and 

information with the other participants and with workshop coordinators, and will be involved in 

writing the report of the excursion as co-authors and in discussing the results. Those that are not 

interested will be only acknowledged as participants. 

Collected herbarium samples will be available for further determination and for documenting the 

activity and as a basis for the exotic flora of the surveyed sites. Samples will be stored in Turkey. 


The thematic workshops on Mediterranean lists, eradication and early warning could take the 

hands-on results into account in their discussions. 



40


The presence, distribution or abundance of many invasive alien plants is positively correlated 

with roads, so roads need to be taken into consideration when planning a survey in a poorly 

studied area. During the two field surveys organized in the framework of the 2nd Workshop on 

Invasive Plants in the Mediterranean Type Regions of the World, 81 alien species were observed 

in the investigated area, i.e. 70 neophytes and 11 archeophytes (including 9 doubtful species), 

with 54 new records for the DAISIE inventory. Three of these species, Acalypha australis, 

Microstegium vimineum and Polygonum perfoliatum, were recorded near a tea factory, and the 

import of material for tea processing is expected to have been their pathway of introduction. The 

results of this survey in the region of Trabzon in North-East Turkey show that roadside surveys 

are a useful tool for early detection efforts, in compiling and updating national or regional 

inventories (especially with time and budget constraints). 

This survey, being organized in the framework of an international workshop, enabled knowledge 

to be shared between experts in the field, and training of students and researchers. These survey 

methods could be adapted, improved, and used elsewhere by others seeking to use early 

detection as part of their overall weed strategy or to gather baseline data on invasive alien plants 

in a poorly studied area. 

These results have been the object of a publication in the EPPO Bulletin, so as to promote the 

initiative and the emerging invasive alien plants found: 

Brundu G, Aksoy N, Brunel S, P. Elias P & Fried G (2011) Rapid surveys for inventorying alien 

plants in the Black Sea region of Turkey. Bulletin OEPP/EPPO Bulletin 41, 208–216. 



41


Building a network for the control of Ambrosia artemisiifolia in the Mediterranean 

Chaired by Mr Christian Bohren (christian.bohren@acw.admin.ch) and Ms Martha Okumu 

(nelmak2212@yahoo.com) 


Ambrosia artemisiifolia is an invasive alien plant causing severe allergies. It is present in many 

European countries (Croatia, France, Italy, Switzerland, etc.). Networks of experts including 

botanists, agronomist and allergists have been created to monitor this species and raise 

awareness among the public. The European Weed Research Society is deeply involved in the 

topic, and has built a network to share information on the species and enhance research into its 

biology and management. 


- To raise awareness on the plant; 

- To build a network of experts interested in contributing to the existing networks on 

Ambrosia artemisiifolia. 


- To investigate the presence/absence, distribution and abundance of Ambrosia artemisiifolia 

in his/her country; 

- The effects and control strategies being adopted to combat the spread of A. artemisiifolia in 

participant's respective countries 


The thematic workshops on) Early Detection and Rapid Response (2.1) and on early warning in 

North-African countries (2.3) might help monitor the species in additional countries. 


The thematic workshop on Building a network for the control of Ambrosia artemisiifolia was 

attended by 12 participants from a wide range of countries including Chile, France, Hungary, 

India, Israel, Italy, Serbia, South Africa and Switzerland. 

The participants shared experiences on the presence of Ambrosia artemisiifolia in their 

respective countries. This included the different pathways of entry, allergenic effects of the 

pollen on human, control methods being employed in the management of the weed, and presence 

or absence of networks of experts to tackle the plant in the various countries. The pathways of 

entry for Ambrosia artemisiifolia seeds in the countries include: water courses, bird mixtures 

(sunflower seeds) and human helped spread pathways like transport by construction machines, 

agricultural products and machinery/equipment. 



42

The participants identified the need for more information on the following topics: 

- Pollen distribution in the air and its allergenic effects. 

- Monitoring and control methods (strategies) for this weed. 

- Biological control agents – how to use, when and where since the implementation part is 

very important. 

- Mapping – production of a single map showing the distribution of the weed in the 

Mediterranean region climate. 

- Other invasive and problematic Ambrosia species, other than Ambrosia artemisiifolia. 

The thematic workshop ended with the remark that Integrated Pest Management methods were 

the best approach for the control of Ambrosia artemisiifolia in the Mediterranean region. 

It was agreed that networking for the control of Ambrosia artemisiifolia in Mediterranean region 

was a noble idea. The existing networks include the European Weed Research Society (Invasive 

Plants Working Group) and the International Ragweed Society (not yet well established). It was 

suggested that the exchange of email addresses and constant communication and sharing of 

information could enhance networking among participants. This was to be reinforced by the 

creation of a Google Group account for the participants. 



43


Measures preventing the introduction of invasive plants in arable crops 

Chaired by Ms Garifalia Economou (cagr2ecg@noc.aua.gr) and Mr Ahmet Uludag 

(ahuludag@yahoo.com) 


Biological invasions are large-scale phenomena of widespread importance, which represent one 

of the major threats to European biodiversity. Regardless of the mechanism, it is clear that the 

impact of the invasive species on natural plant communities, may also cause major economic 

problems, with invasive species becoming established as highly persistent and vigorous 

agricultural weeds, damaging manmade environments or choking open spaces and waterways. 

Several economic and environmental drivers markedly increase ecosystem vulnerability to 

invasion such as agriculture land and particularly arable crops. Species such as Solanum 

eleanifolium, Ipomoea hederacea in corn, Avena fatua, in winter wheat and Conyza albida in 

alfalfa are considered as the most problematic, fast- growing, easily propagated and vigorous 

competitors in the arable crops listed above in the Mediterranean zone. It is widely known that 

the application of conventional weed control methods has proved inadequate to prevent the rapid 

dispersal of these invasive species to a variety of habitats and therefore to enter crop fields. The 

prevention and mitigation of impacts of invasive species demands the action of ―developing 

measures aimed at the control of invasive alien genotypes as well as specific actions including 

an early warning system‖. Through this workshop the experts will draw on their experience in 

order to create a baseline for priorities definition at a regional scale. 


Documentation of the problem 

- Reference to the arable crops invaded by alien species 

- Reference to the main invasive alien plants 

- Assessment of the invasive plants abundance and population trends 

- Effect of climatic change on alien plant invasion 

- Proposed control methods 

Tasks for the coordinators prior the workshop 

A document will be circulated to the participants describing: 

- the thematic issues in order to collect updated data in respect to their experience 

- the control methods that proved ineffective at a regional scale 

- the agronomic practices and the land use change at a regional scale 

- Climatic data at a regional / country scale 

Task for the participants prior to the workshop 

The participants should have collected information prior to attending. 



44


- General work on list of alien plant invasion 

- Thematic workshops on eradication and early warning. 


Fifteen (15) colleagues participated in the thematic workshop from nine (9) countries: Armenia, 

Greece, Iran, Lithuania, Morocco, Serbia, Sudan, Tunisia and Turkey. 

The concept of the project was driven by the need to investigate the agronomic and 

environmental factors that increase the arable crops vulnerability to invasion of alien species. 

Arable crops, related either to human diet (cereals, corn, sunflower) or to human life 

improvement (fibber plants, biofuel crops) are of major importance. Taking action for 

developing measures to control invasive alien genotype is primordial, including an early warning 

system. Arable crops are characterized by a small life cycle and are bad competitors with alien 

plants which have a fast and vigorous growth and spread easily. In addition, the application of 

the conventional weed control methods proved inadequate to prevent their rapid spread. The aim 

of the thematic workshop was to document the problem at a country/regional scale with 

particular reference a) to the main invasive alien plants, b) to the arable crops invaded by alien 

species, c) to the assessment of the invasive plants abundance and population trend, d) to the 

effect of climatic change on alien plant invasion and e) to propose control methods. 

The participants achieved the following results during the thematic workshop: 

- The elaboration of a questionnaire about Invasive Alien Plants in Arable Crops, 

- The distribution of the questionnaire to the participants in order to be completed with 

additional tasks, data and comments for improvement, 

- To focus on the effects of climate change on alien plants invasions taking into 

consideration the parameters proposed by the model ―AquaCrop‖ registered by FAO with 

the objective to ―Estimate Climate Change Impacts on cotton, wheat, maize and sunflower 

in Greece using FAO‘s Crop Water Productivity Model AquaCrop‖, 

- To establish a permanent scientific process as a Small Working Group in order to create a 

baseline for priorities definition at a regional scale in each represented country, 

- To analyze the data, this will be gathered through a questionnaire, to be potentially 

published by EPPO if possible. 


- General work on list of alien plant invasion 

- Thematic workshops on eradication and early warning. 


Fifteen (15) colleagues participated in the thematic workshop from nine (9) countries: Armenia, 

Greece, Iran, Lithuania, Morocco, Serbia, Sudan, Tunisia and Turkey. 

45 


2 nd The concept of the project was driven by the need to investigate the agronomic and 

environmental factors that increase the arable crops vulnerability to invasion of alien species. 

Workshop on Invasive alien plants in Mediterranean type regions of the world



46

Oral presentations 



47

The impacts of global change on plant life in the Mediterranean and the spread of invasive 

species 

V H Heywood 

School of Biological Sciences, University of Reading, Reading RG6 6AS, UK. E-mail: 

v.h.heywood@reading.ac.uk 

Introduction 

The Mediterranean region is a focus of attention because of its unique climatic 

features. It is widely agreed that it is one of the areas that will be severely 

impacted by accelerated climate during the 21st century with higher 

temperatures and increasing aridity projected by most models. Because of the 

lack of a hinterland that characterizes the climatic zone of the comparable 

Saharan hinterland, a new no-analogue climate will develop in Mediterranean 

Europe. The migration of plant species from south to north during the 

timescale of concern will be limited by the barrier that the Mediterranean Sea 

represents. As a result of this new climate and its interaction with other 

components of global change such population movements and changes in 

disturbance regimes (e.g. increased frequency and duration of forest fires), 

substantial changes in the composition of the vegetation may be anticipated as 

a result of the differential success of individual species in adapting to the 

changing climate, migrating to track their climate envelope or becoming 

extinct and no-analogue communities will develop. This will be particularly 

notable in the case of forest communities and tree species. Some species will 

probably arrive through long-distance dispersal and these will compete with the 

remaining resident species. The new species assemblages will be vulnerable to 

invasive and weedy species, and it is probable that those invaders which 

already occur there will persist or extend their ranges while new species will 

become established. Strategies to try and mitigate the expected increase in the 

impacts of alien invasive species in the region need to take into consideration 

not just the conditions today but the new climates and species assemblages that 

will develop as a consequence of global change. 

‗Scientific and societal unknowns make it difficult to predict how global environmental changes 

such as climate change and biological invasions will affect ecological systems‘, Hellmann et al. 

(2008) 

An increased risk of invasion by non-native species is one of the commonly cited 

consequences of climatic and other aspects of global change (Peterson et al., 2008; NAS, 2002; 

Hulme et al., 2009). In the case of the Mediterranean, the general perception until recently has 

been that the region‘s ecosystems are less vulnerable to invasion than similar ecosystems 

elsewhere, largely because of the long history of human interaction with the environment which 



48

has left them with greater resilience (Lavorel, 1999 1 ). Such a view is no longer tenable, 

especially for Mediterranean islands (Traveset et al., 2008; Hulme et al., 2008) and a notable 

increase in invasive species has been recorded in recent years (Hulme, 2004; see below). This is 

partly as a consequence of major anthropogenic impacts in the region arising out of population 

growth and movements, industrialization, changes in agriculture, a massive growth in tourism 

and increased globalization, and partly as a result of better reporting. While some countries such 

as Spain have invested considerable resources in recording invasive alien species (e.g. Sanz- 

Elorza et al., 2004; Andreu & Vilà, 2010; Crosti et al., 2010) underreporting of invasive species 

is still a major problem in the Mediterranean region, especially in the east and south of the 

region. A global scale survey of indicators of biological invasion by McGeoch et al. (2010) 

indicated that the number of documented invasive alien species may be affected by country 

development status which is associated with low investment in research and data collation. It has 

also been suggested that because the Mediterranean region has already been subjected to a major 

extinction event in an earlier period, it is more resistant now to further change (Greuter, 1995). 

The emphasis in this paper is deliberately on the consequences of global change, not just 

accelerated anthropogenic climate change, on the region‘s plant life and its implications for the 

extent of plant invasion in the Mediterranean. Global change comprises demographic change and 

population movements, changes in disturbance regimes such as fire, and the various components 

of climate change, all of which interact with each other (Box 1). In addition societal and 

technological changes also need to be taken into account. As Hellmann et al. (2008) have noted, 

‗Scientific and societal unknowns make it difficult to predict how global environmental changes 

such as climate change and biological invasions will affect ecological systems‘, 

It is essential to take into account all the interacting drivers of global change in attempting to 

assess their impacts on plant invasions in the Mediterranean. These interactions make it difficult 

to disentangle the role of individual drivers and increase our uncertainty as to their effects (Pyšek 

et al., 2010). As Vilà et al. (2007) comment, ‗these ongoing changes … decrease our capacity to 

predict which introduced species are most likely to become invaders and which ecosystems are 

most vulnerable to invasion‘. Consequently, in assessing the likely extent of invasion in the 

Mediterranean region as a consequence of global change, we need to know what kinds of 

ecoclimatic scenarios will develop in the region and the socio-economic conditions and therefore 

the answers to a series of interrelated questions: 

What will be the new climatic conditions that will develop and prevail in the region (e.g. 

anticipated changes in temperature and precipitation leading to increased aridity)? 

What impact will these changes have on disturbance regimes such as fire, agricultural 

practices? 

What demographic changes and population movements will occur and what will be the 

new pattern of tourism? 

What kind of flora and vegetation will develop as a consequence of all these changes? 

1 Lavorel cautions against the misuse of the term ‗resilience‘ 



49

Box 1 - The main components of global change 

Population change 

Human population movement/migrations 

Demographic growth 

Changes in population pattern 

Changes in land use and disturbance regimes 

Deforestation 

Degradation, simplification or loss of habitats 

Loss of biodiversity 

Climate change (IPPC definition) 

Temperature change 

Precipitation change 

Atmospheric change (greenhouse gases: carbon dioxide, methane, ozone, and nitrous 

oxide) 

Other climate-related factors 

Distribution of Nitrogen deposition 

Global dust deposition (including brown dust and yellow dust) 

Ocean acidification 

Air pollution in mega-cities 

Only then can we make any confident predictions as to the likelihood of existing invasive 

species persisting or spreading and of new alien invasive species successfully arriving by 

whatever pathway, competing with the old and new resident species and becoming established 

and spreading. Predicting potential invasions is notoriously difficult even in relatively stable 

conditions. Doing so in a context of global change, and accelerated climate change in particular, 

is a challenge whose complexity we are only just beginning to understand. 

The Mediterranean climate 

The Mediterranean region has attracted a great deal of attention because of its unique 

characteristics: its semi-enclosed sea, elongated shape, large topographic contrasts and climate 

gradient from mid-latitude to subtropical and its great sensitivity to climate change (Lionello et 

al.,2008). The climate is transitional between the dry tropics and temperate Europe and is unique 

because of the lack of a hinterland that characterizes the climatic zone of the comparable Saharan 

hinterland. This combination of circumstances makes it a no-analogue climate and the vegetation 

that has developed there is also transitional and highly sensitive to relatively small climatic 

changes. As Ortolani & Pagliuca (2006) note the Mediterranean region ‗is highly sensitive to 

variations in climate and environment. Indeed, shifts in the climate bands towards north or south 

by only a few degrees of latitude may result in dramatic changes in soil surface conditions. This 

may cause, for example, desertification in areas that previously had a humid climate or vice 

versa‘. 



50

While it is widely recognized that the normally benign climate of the Mediterranean basin has 

been favourable to the development of several civilizations over time , it shows considerable 

variation – in temperature and precipitation according to latitude, longitude, altitude, 

topography, regional winds (Mistral, Tramontane, Bora, Etésiens, Sirocco) and other factors 

even within short distances (Harding, 2006) – and frequently presents episodes of extreme 

temperature, prolonged drought and torrential rainfall that demand a fair degree of resilience 

from its inhabitants. 

Predicted changes in the Mediterranean climate 

A review of climate change projections over the Mediterranean region by Giorgi & Lionello 

(2008) based on the latest and most advanced sets of global and regional climate model 

simulations gives ‗a collective picture of a substantial drying and warming of the Mediterranean 

region, especially in the warm season (precipitation decrease exceeding − 25–30% and warming 

exceeding 4–5 þC). The only exception to this picture is an increase of precipitation during the 

winter over some areas of the northern Mediterranean basin, most noticeably the Alps. Interannual 

variability is projected to generally increase as is the occurrence of extreme heat and 

drought events‘. There is still uncertainty regarding precipitation trends but an increase of up to 

10 per cent in winter precipitation and a decrease of 5 to 15 per cent in summer precipitation by 

the latter half of the 21st century are suggested by some models (Karas, 2000). 

The long-term projection is for continued warming as the influence of greenhouse gases 

increases over time. A global temperature increase of 2þC is likely to lead to a corresponding 

warming of 1 to 3þ in the Mediterranean (Giannakopoulos et al., 2005). Temperature scenarios 

for the Mediterranean have been estimated by Hertig & Jacobeit (2008) whose assessment 

indicated that even with a high level of uncertainty regarding the regional distribution of climate 

change in the region, ‗substantial changes of partly more than 4 o C by the end of the century have 

to be anticipated under enhanced greenhouse warming conditions‘. Temperatures are likely to 

be higher inland than along the coast and the largest increase will take place during the summer 

(Giannakopolous et al., 2005). This will have a serious impact on the evaporation rates and water 

budget and availability in the region which is likely to be at increased risk of water shortages, 

forest fires and loss of agricultural land. Gao & Giorgi (2008) used three measures of aridity to 

estimate the possible effects of late 21 st century climate change on the Mediterranean area and 

their analyses suggest that the region might experience a substantial increase in the northwards 

extension of dry and arid lands, especially in central and southern parts of the Iberian, Italian, 

Hellenic and Turkish peninsulas and in areas of southeast Europe, the Middle East, north Africa 

and the islands of Corsica, Sardinia and Sicily. They identified the southern Mediterranean 

region as especially vulnerable to water stress and desertification as a result of these climate 

changes. 

The frequency of extreme weather events such as heat waves, torrential rains and droughts are 

expected to increase. The overall effect of these changes will be a northward shift and expansion 

of the Mediterranean-climate zone with a ‗saharization‘ in the southern part. 



51

A different approach was taken by Klausmeyer & Shaw (2009) who determined the projected 

spatial shifts in the Mediterranean climate extent (MCE) over the next century for the five 

Mediterranean climate regions of the world 2 . They showed that the median projection of the 

future MCE in the Mediterranean Basin is larger than the current MCE, but most of the 

atmosphere-ocean general circulation models (AOGCM) simulations project contractions in 

Morocco and in the Middle East (see their Fig. 2). They note that high topographic diversity and 

contiguous land toward the nearest pole provide room for the expansion of the MCE in Greece, 

Turkey, Spain and Portugal whereas in Morocco, the Atlas Mountains provide topographic 

diversity, but the Mediterranean Sea blocks expansion toward the north. 

Interaction with other factors of global change 

An important consideration is how the projected climate changes in the Mediterranean will 

interact with other components of global change, notably changes in disturbance regimes. 

Sinclair et al. (2010) suggest that ‗changed patterns of habitat fragmentation and connection are 

likely to have at least as large an impact as climate change in the medium term, both as problems 

and solutions…‘. Human transformation of the Mediterranean landscapes can affect the ability 

and rate of migration of species in response to climate change (cf. Midgley et al., 2007). 

Wild-fire risk 

Fire has been a powerful factor in shaping the landscapes and plant communities in the 

Mediterranean region and in the evolution and differentiation of the flora. In European 

Mediterranean countries in particular, large fires induced by past land-use changes are the main 

driving factor in landscape and ecosystem dynamics. Fire was the driving force in the coevolution 

of Mediterranean humans and landscapes in the Pleistocene (Naveh,1991) and since 

the beginnings of this interaction between humans and the environment, the causes of wildfires 

have been increasingly anthropogenic and today account for 90–95% of the fires recorded. 

About 600 000 ha of Mediterranean forest burns each year. Land use changes such as movement 

away from the countryside in the northern rim has led to the development of large areas of 

continuous vegetation that are susceptible to wild fires (MRFA, 2009). 

Climate change with higher summer temperatures and reduced precipitation is expected to 

lead to an increase in fire risk and disruption of natural fire regimes. There is evidence that the 

incidence of heat waves shows a correlation with the amount of forest burned (e.g. Colacino & 

Conte (1993a, b)). The area of fire-risk will expand northwards in line with the climate shift and 

also in the eastern and southern Mediterranean (e.g. Syria, Lebanon, Algeria) according to 

MFRA (2009). 

Changes in land use will not only affect the migration of species in the face of climate change 

but also the dispersal and spread of invasive alien species as they have to move across 

landscapes. As Vilà et al. (2007) comment, it is surprising that there have been so few studies on 

the interactions between the patterns of invasion and changes in land use or cover. 

2 They used Aschmann‘s (1973) ‗conservative‘ definition of the Mediterranean climate and excluded areas 

traditionally included in the biome nsuch as the south coast of France, western Italy, northeastern Spain. 



52

As well as the major transformations that have taken place in the landscapes in earlier periods, 

the Mediterranean basin has witnessed considerable changes in land use in recent decades, 

especially in the agricultural sector – where there are considerable differences between the trends 

in the northern part of the basin and the southern and eastern parts in terms of area under 

cultivation, crop substitutions, and agricultural intensification – and the forestry sector, and the 

balance between them and the native vegetation. In the northern part, movement from the land 

and abandonment of cultivation has led to an increase in forests, giving rise to large continuous 

areas of unmanaged forests and scrubland while urban development and tourism, especially in 

coastal areas has led to habitat fragmentation and biodiversity loss. In the eastern and southern 

sectors, there has been considerable conversion of forests into grazing and agricultural cropland 

while others have been degraded. This has resulted in land degradation and desertification. 

Land use changes often lead to the disturbance and fragmentation of natural habitats which 

are well known to favour plant invasions. These changes will be intensified by climate change in 

the Mediterranean as the differential adaptation/survival, migration and extinction of individual 

species leads to the disassembly plant communities and the formation of new assemblages of 

species and the creation of gaps that will provide opportunities for the entry of invasive species 

which, if they establish successfully, will form part of the ‗new‘ species groupings. 

Tourism 

The Mediterranean is the leading tourist destination in the world visited by 147 million 

international tourists in 2003, representing 22% of the international tourism market, and 

generated US$113 billion for the region (WT0, 2003. 70% of these tourists visited just two 

countries, Italy and Spain. Over 12 million tourists visit the Mediterranean islands each year. On 

the other hand, the response to uncomfortably high summer temperatures in the Mediterranean 

could change the timing of visits with higher tourist numbers in the spring, autumn and winter. 

Also, predicted warmer temperatures in non-Mediterranean Europe could change the destination 

of tourists with adverse effects on the Mediterranean economy. 

The increase of tourism has led to massive urban and tourist-related development with 

accompanying infrastructural effects such as irrigation, drainage, desalinisation, large-scale 

transport infrastructures and so on which has led to the phenomenon known as ‗coastalization‘ 3 – 

the concentration of population and economic activities on coastal spaces which has inevitably 

led to an impoverishment of biodiversity, loss or fragmentation of habitats. 

The effects on the landscapes are all too visible but what is not so obvious is that this radical 

transformation of entire areas caused by tourism leads to soil erosion, increased pollution 

discharges into the sea, loss of natural habitat , increased pressure on endangered species and 

3 Described as ‗Linear and nuclear concentrations along the coast […] phenomena that are directly linked with 

intensive housing development, indiscriminate land occupation, and the possession of large reserves of land which it 

is possible to build on‘ in the conclusions of the International Congress, ‗Sustainable Tourism in the Mediterranean: 

The Participation of Civil Society‘, 1998. MED Project ULIXES 21. For Sustainable Tourism in the Mediterranean. 



53

heightened vulnerability to forest fires. Significantly, it puts a strain on water resources, which 

are already a critical issue in the Mediterranean: it is estimated that for instance, an average 

Spanish inhabaitant uses 250 litres of water per day while the average tourist uses up to 880 

litres. The influx of tourists can also lead to the disruption of traditional cultures. 

One of the unexpected consequences of tourism is the increased threat of invasive plants 

being introduced as part of the landscaping schemes of the tourist hotels and complexes. The 

Mediterranean region is already the adopted home of many tropical and subtropical plants, 

notably trees, shrubs and palms and new species are being introduced through nurseries for both 

landscaping and domestic use. The nursery trade has developed and expanded considerably in 

the Mediterranean in the last two decades: the Pistoia region of Italy, for example, has the largest 

concentration of plant nurseries in Europe covering more than 5,500 ha. Given that the 

horticultural trade is the major pathway for plant invasions (Reichard & White, 2001) great 

vigilance is needed to ensure that this expansion of the ornamental nursery trade does not lead to 

a corresponding rise in new plant invaders. 

Predicting the impacts of climate change on the Mediterranean flora and vegetation 

It is widely agreed that the flora and vegetation of the Mediterranean region are the most 

vulnerable in Europe to climate change because of their sensitivity to drought and rising 

temperatures and the fact that they are already under stress (EEA 2005; Giannakopoulos et al., 

2005; Lavorel, 1999). 

The challenges of predicting the impacts that climate change will have on ecosystems are 

complex and have been addressed by modeling, experimental and observational approaches 

(Midgley et al., 2007). The major difficulty is that individual species react in different ways to 

climate change and it is the outcome of these reactions in combination if these that makes up the 

ecosystem response. As Klausmeyer & Shaw (2009) observe, ‗Projecting how plant assemblages 

will shift in response to climate change is subject to significant uncertainty because it requires 

compounding the uncertainty with projecting climate change with the uncertainty inherent in 

projecting future distributions of individual species‘. 

The tool that is most frequently used in attempting to predict the responses of species to 

climate change is bioclimatic modelling. Bioclimatic models (bioclimatic envelope models) are 

a special case of ecological niche or distribution models. Today, most current projections of the 

future migration of plants are based on the use of ‗climate envelope‘ or bioclimatic modeling 

techniques (Nix, 1986; Guisan & Thuiller, 2005) in which projected future distributions are 

based on the current climate in the species‘ native range. These modeling techniques combine 

computer-based models of the current climate on the one hand, with information on the current 

distribution of species on the other hand, to establish a bioclimatic 4 niche model and this model 

of optimal environmental parameters is then fitted to a range of future climate scenarios to 

establish likely shifts in environmental optima for species. The models are used to help predict 

the potential geographic range responses of species to climate change. Bioclimatic modeling has 

been applied extensively in Europe and other parts of the world. There is no single standard 

4 also known as edaphic, fundamental, environmental or Grinellian models. 



54

approach and techniques are constantly being developed (for a review see Elith & Leathwick, 

2009). 

Bioclimatic models are of course simplifications of reality and primarily important aids to 

research as Thuiller et al. (2008) point out. Modeling techniques aim defining the climate 

‗envelope‘ that best describes the limits to its spatial range for any choosen species by 

correlating the current species distributions with selected climate variables. Although they are 

commonly referred to as predictions, their proper role is to contribute to the information base on 

which predictions of future change are made. 

Climate envelope modelling is a valuable and powerful tool in our efforts to understand the 

interaction between species distributions and climate and to work out the likely impacts of 

climate change on biodiversity. However, the models currently employed have severe limitations 

and make a number of assumptions that reduce their value and effectiveness (Jeschke & Strayer, 

2008). Most models are unable to take into account factors such as dispersal capacity, migration 

processes, biotic interactions, the capacity of species to adapt to climate change and the range of 

genetic variation in species populations (Heikkinen et al., 2006; Brooker et al., 2007; Thuiller et 

al., 2008; Buisson et al., 2010) while those that do make simple assumptions about migration 

such as nomigration or complete migration. Many species migration will be hindered by natural 

barriers such as mountains or lakes and by large scale landscape developments such as 

urbanizations, industry and roads which will limit the connectivity necessary for successful range 

shifts as an adaptation to climate change. 

The models are rarely tested by independent validation (Jeschke & Strayer, 2008). Moreover, 

the quality of the niche models depend on the quality and sufficiency of underlying data, and in 

many cases lack of detailed data on distribution of species is a limiting factor for resolution, 

coverage or both. Bioclimatic models have also been criticized by Willis & Bhagwat (2009) and 

Ackerly et al. (2010) for their coarse spatial scale so that they fail to take into account 

microtopography and their use may therefore exaggerate the scale of loss of species. The latter 

suggest that ‗Fine-scale spatial heterogeneity may provide a critical buffer at a landscape and 

reserve scale, enhancing genetic and species diversity and reducing gene and organismal 

dispersal distances required to offset climate change, at least in the short run‘. On the other 

hand, in the case of many Mediterranean mountain/alpine species with highly specialized habitat 

requirements, their limited dispersal capacity and the non-availability of suitable niches are 

likely to be limiting factors in their survival, no matter how fine the scale of modelling applied. 

Buisson et al. (2010) propose that forecasts of the impacts of climate change should always carry 

an assessment of their uncertainty, so that those charged with making management and 

conservation decisions can do so in the full knowledge of the reliability of the models. 

A further important consideration, and one that has received less attention as Fitzpatrick & 

Hargrove (2009) point out, is that the bioclimatic models are usually extrapolated into 

environments which differ from those that characterize the region in which the models are 

calibrated. In the case of the Mediterranean basin, new, no-analogue environments will be 

created as a consequence of the climatic shifts and other elements of global change. 



55

Models must be interpreted on the basis of our knowledge of the biology of the organisms 

being modelled although for many species such knowledge is often quite limited and it is clear 

that we need to undertake much more research into the biological characteristics, dispersal 

capacity and adaptive range of species that are likely to be at risk. Moreover, the long-term 

human impacts on the vegetation of the Mediterranean have had long-term consequences for the 

dynamics of the current landscapes which have also to be taken into account in modelling the 

impacts of climate change (Pausas, 1999). 

Various studies have been made of the likely impacts of climate change on Mediterranean 

flora and vegetation (Bakkenes et al., 2002; Thuiller et al., 2005; CEC, 2007; Schröter et al. 

2005; Berry et al. 2007a, b) which suggest that many species would have to migrate north or 

altitudinally to track their climatic envelope. While it is not anticipated that there will be biome 

shifts, Peðuelas & Boada (2003) have in fact documented such a shift in Mediterranean 

mountains in recent times: they compared historical data and correlated them with climate data 

over the last 50 years that showed a temperature increase of 1.4þC and no change in the total 

precipitation. They found that Quercus ilex progressively replaced heather (Calluna vulgaris) 

and beech (Fagus sylvatica) in the higher elevations. 

A number of ecological modeling approaches have been developed that estimate vegetation 

development (productivity or vegetation type) under climate change. These include statistical 

species distribution models, gap models, landscape models; biogeochemical models and dynamic 

global vegetation models. For a discussion of these see Robinson et al. (2008). 

While we can use various types of model to predict the possible migrations of species to track 

their new climatic envelopes, what we cannot do with existing modeling approaches is to predict 

with sufficient accuracy what the new vegetation cover will be nor the overall environmental 

conditions, in areas impacted by climate change. This applies both to the move-out areas and the 

move-in areas, a distinction that is not often made but which may be critical in some parts of 

Europe such as the Mediterranean zone as mentioned above. Since the likelihood of survival and 

multiplication of migrant species will depend on the environmental context into which they 

move, not to mention stochastic factors which may intervene, we have to accept that our present 

understanding of the consequences of climate change is severely limited and sometimes 

dependent on little more than intelligent speculation. If we add to this the level of uncertainty 

that still surrounds the details of the extent of climate change and their impact at a local level, 

much of our planning has to be broadly based rather than site-specific, such as modifying or 

enhancing our protected area systems, or precautionary such as employing ex situ 

complementarity (Heywood, 2010) 

As noted above, it is often asserted that climate change will favour invasive species or 

increase the risk of invasions but as Hellmann et al. (2008) comment few authors have identified 

specific consequences. They then propose five potential consequences: 

Invasion pathways: altered mechanisms of transport and introduction 

Altered climatic constraints 

Changes in distribution of existing alien species 

Changes in impacts of existing invasive species 

Changes in effectiveness of management strategies 

56 


2 nd Workshop on Invasive alien plants in Mediterranean type regions of the world

Bioclimatic models have been used to project the future ranges of invasive species but are of 

course subject to the same limitations and constraints as other species (Jeschke & Strayer 2008) 

Non-modelling approaches 

Although bioclimatic modeling is the commonest method of suggesting the likely response of 

species to climate change, the vulnerability of species to climate change can also be assessed on 

the basis of their biological and ecological characteristics, and other factors, that determine their 

sensitivity, adaptive capacity and exposure to climate change (Gran Canaria Group, 2006; 

CBDF/AHTEG 2009) (see Box 2). 

Box 2 - Criteria for identifying taxa vulnerable to climate change (Gran Canaria Group, 2006) 

Taxa with nowhere to go, such as mountain tops, low-lying islands, high latitudes and edges of 

continents; 

Plants with restricted ranges such as rare and endemic species; 

Taxa with poor dispersal capacity and/or long generation times; 

Species that are susceptible to extreme conditions such as flood or drought; 

Plants with extreme habitat/niche specialization such as narrow tolerance to climate-sensitive 

variables; 

Taxa with co-evolved or synchronous relationships with other species; 

Species with inflexible physiological responses to climate variables; 

Keystone taxa important in primary production or ecosystem processes and function, and 

Taxa with direct value for humans or with potential for future use. 

Species migrations in the Mediterranean region 

At the core of projections of the future distribution of species in the face of climate change is 

their migration capacity and the dispersal ability. The ability of species to track their shifting 

climate space and their ability to adapt to the conditions in the new habitats are critically 

influenced by the individual dispersal capacity of species (Hoegh-Guldberg et al., 2008; Massot 

et al., 2008). However, as Thuiller et al. (2008) comment, although the importance of plant 

migration in response to global change is widely acknowledged, few modelling studies explicitly 

include migration processes when simulating geographical plant responses. In practice, our 

knowledge of the potential migration rate of species is seriously inadequate for most species and 

this limits our current capacity to predict the impacts of accelerated climate change on the future 

geographic distribution of species (Midgley et al., 2007). 

Faced with a changing climate and changing environmental conditions, plant species will 

react in different ways: they may persist in situ and keep their current range or in the case of 

short-lived species they may adapt to the new conditions over time through selection of suitable 

genotypes; or they may respond with range expansions through migration or their distribution 

area may contract or shift. 



57

Some species will be able to migrate out of the current Mediterranean zone and track 

their climatic envelope northwards or altitudinally. 

Some species will be able to adapt in situ to the changing climate 

Some species will migrate from the southern to the northern shores of the Mediterranean 

by long-distance dispersal 

Some species will not be able to adapt in situ or to migrate and therefore will become 

locally, or in the case of range-restricted species, totally extinct. 

Some existing invasive species will colonize niches left vacant and spread 

Some new alien invasive species will successfully occupy vacant niches and spread 

Although our understanding of the ability of plants to respond to their environment has 

developed greatly (van Kleunen & Fischer, 2005; Valladares et al., 2007), for most species the 

precise range of their phenotypic and physiological responses to the present climate, let alone 

changing climatic conditions, is very limited and much further research is needed to gain a 

deeper understanding of the adaptation possibilities of individual species in situ to climate 

change. Also, our knowledge of the amount of genetic variation in their existing populations is 

generally poor. In addition, there has been an increased interest in the role of epigenetic variation 

and processes in the ecology and evolution of plant species (Bossdorf et al., 2008; Richards et 

al. 2010 a,b) and a recent paper has shown that the environment can alter the epigenetic context 

of individual species of European common marsh orchids and that Darwinian selection acts on 

epigenetic variation in the same way as on the genetic information, leading to adaptation and 

divergence between species within a small number of generations (Paun et al., 2010). This has 

given rise to the hope that some plant species may be able to adapt more quickly to 

environmental change than previously thought and thus be able to combat rapid climate change. 

Population epigenetics is however in its infancy and is still a matter of intense debate and one 

can only speculate about its true significance and potential role in adapting to climate change. 

The lack of a hinterland will act as a major constraint on the availability of migrants and 

coupled with the barrier of the Mediterranean Sea to northward migration makes it difficult to 

imagine what type of vegetation will occupy this space without extensive migration of species 

from North Africa although some species will probably arrive through long-distance dispersal. 

The whole issue of long-distance dispersal takes on a new importance when considering the 

migration of species due to climate change and there had been renewed interest in the potential 

role of rare long-distance dispersal (LDD) events as drivers of rapid plant migrations (Pearson & 

Dawson, 2005). It is of course possible that low probability LDD events may allow propagules 

of some species to reach the southern shores of the Mediterranean within the short timescale 

envisaged, although there is no guarantee that this will lead to successful establishment or spread 

as this will depend on habitat availability and its permeability, life history and biological 

characteristics (Higgins & Richardson, 1999). 

The vegetation will be vulnerable to invasive and weedy species and it is probable that those 

which already occur there will persist or extend their ranges while new species will become 

established. 

If the gaps created by the migration of species tracking their climate envelopes, are not filled 

by inward migration, the vegetation will be vulnerable to invasive and weedy species and its is 

58 



probable that at least some of those invasive plants which already occur there will persist or 

extend their ranges while new ones will become established. On the other hand, as already 

noted, the impacts of climate change on the invasive potential of species are still poorly 

understood. 

The plants and vegetation of Mediterranean Europe will experience unique problems and the 

region will see a major increase in weedy, alien invasive and pioneer species in coastal and 

lowland habitats. Some restricted area endemics, especially in mountain habitats, are expected to 

become extinct but will not be affected by alien invasive species. 

Consequences of climate change for Mediterranean forests 

While it is not possible to predict with any degree of accuracy the composition and nature of 

the new species assemblages that will develop in the new climatic spaces of the Mediterranean, 

we can gain some idea of the impacts on some of the major vegetation types through tracking the 

likely movements of keystone forest species such as the oaks and pines. Although Mediterranean 

forest and woodlands cover only 73 million ha or about 8.5% of the region‘s area (MRFA, 

2009), they represent an important component of the vegetation (Palahi et al., 2008) and house a 

significant proportion of plant and animal diversity, including c.290 species of indigenous trees 

(Quézel & Médail, 2003). The ways in which global change affects them in the coming decades 

is therefore a matter of considerable concern. 

How far forests and their keystone species will be resilient to climate change, especially 

higher temperatures and increasing aridity, has been studied in a number of instances. Some 

studies have been made on the effects of climate change on the distribution of Mediterranean 

forests and their adaptation (see summary by Regato, 2008). A review by Resco de Dios et al. 

(2007) suggests that ‗Climate change compounded with trends of rural abandonment are likely to 

diminish forested areas within the Mediterranean basin that will be replaced by fire prone shrub 

communities. This could be favoured by outbreaks of pathogens, fire and other large scale 

disturbances. Landscape fragmentation is expected to impede species migration‘. Modelling 

studies on individual tree species have been carried out, for example in the Iberian Peninsula 

(Benito Garzñn et al., 2008; Linares & Tiscar, 2010), or in France (Gaucherel et al., 2008). The 

dynamics of changes in forest tree species ranges are, however, difficult to predict, as Regato 

(2008) notes, because of lags in adult mortality and the self-regulatory mechanisms of forest 

populations which may create resistance to range contractions. Also, it should be remembered 

that the current species distribution ranges may differ significantly from the potential species‘ 

climate envelope. In such cases they may greater potential for in-situ adaptation to climate 

change before reaching their migration threshold. 

Conclusions 

The Mediterranean basin possesses a unique and diverse climate which is matched by the 

varied topography of the region. Combined with a long history of human interaction, this has 

resulted the great diversity and richness of the vegetation that exists today. Although the region 

had previously not been considered at serious risk from invasion by alien plant species, recent 



59

evidence has shown such a view is not correct and there is now the concern global change, 

especially accelerated climate change, will increase the extent of invasions. 

It is notoriously difficult even in relatively stable conditions to predicting potential invasions 

but doing so in a context of global change is a challenge whose complexity we are only just 

beginning to understand. Before we even begin to attempt to do so, we firstly have to try to 

interpret the evidence of how the climate will change and how it will interact with other factors 

such as population change and movements and changes in disturbance regimes. Only when we 

have as good evidence as possible about the movements of climate space can we attempt to 

project the impacts of these changes on the species and ecosystems. There is still considerable 

uncertainty in modelling projections of climate change and the use of bioclimatic models to 

project the future distributions of individual species. Bioclimatic modelling has proved to be a 

valuable tool in helping project the future distributions of species (including potential IAS) but 

the limitations of the models need to be acknowledged and it noted that they are usually 

extrapolated into environments which differ from those that characterize the region in which the 

models are calibrated. A new no-analogue climate will evolve in the Mediterranean. As a 

consequence of these new climatic conditions and the barrier that the Mediterranean Sea 

represents for plant migration, new species assemblages will develop, although their detailed 

composition cannot be predicted accurately, and are likely to be vulnerable to invasion by 

expansion of the ranges of existing alien species or by those new species that are able to reach 

them. This will pose major challenges for the prediction of invasions and the development of 

strategies to prevent them or mitigate their effects. Until further improvements are made to 

bioclimatic models and they are validated independently, we need to be cautious about 

interpreting the results and pay more attention to trying to determine the future climatic and 

ecological conditions of the areas of concern and the migration and dispersal capacity of both the 

native species and the potential invaders. 

References 

Ackerly DD, Loarie SR, Cornwell WK, Weiss SB, Hamilton H, Branciforte R & Kraft NJ B (2010) The geography 

of climate change: implications for conservation biogeography. Diversity and Distributions 16, 476–487. 

Andreu J & Vilà M (2010) Risk analysis of potential invasive plants in Spain. Journal of Nature Conservation 18, 

34–44. 

Aschmann H (1973) Distribution and peculiarity of Mediterranean ecosystems. In: Di Castri F, Mooney HA, (Eds.) 

Mediterranean Type Ecosystems; Origin and Structure. Springer-Verlag, Berlin & New York. 

Bakkenes M, Alkemade JRM, Ihle F, Leemansand R, Latour JB (2002) Assessing effects of forecasted climate 

change on the diversity and distribution of European higher plants for 2050. Glob Change Biol 8, 390–407. 

Benito Garzñn B, Sánchez de Dios R & Sainz Ollero H (2008) Effects of climate change on the distribution of 

Iberian tree species. Applied Vegetation Science 11, 169-178. 

Berry PM, Jones AP, Nicholls RJ & Vos CC (2007a) Assessment of the vulnerability of terrestrial and coastal 

habitats and species in Europe to climate change, Annex 2 of Planning for biodiversity in a changing climate 

– BRANCH project Final Report, Natural England, UK. 

Berry PM, O‘Hanley JR, Thomson CL, Harrison PA, Masters GJ & Dawson TP (2007b) Modelling Natural 

Resource Responses to Climate Change (MONARCH): MONARCH 3 Contract report. UKCIP Technical 

Report, Oxford, UK. 

Bossdorf O, Richards CL & Pigluicci M (2008) Epigenetics for ecologists. Ecology Letters 11, 106–165. 

Brooker RW, Travis JMJ, Clark EJ & Dytham C (2007) Modelling species‘ range shifts in a changing climate: The 

impacts of biotic interactions, dispersal distance and the rate of climate change. Journal of Theoretical 

Biology 245, 59–65. 



60

Buisson L, Thuiller W, Casajus, N, Lek S. & Grenouillet, G (2010) Uncertainty in ensemble forecasting of species 

distribution. Global Change Biology 16, 1145–1157. 

CBDF/AHTEG (2009) Draft Findings Of The Ad Hoc Technical Expert Group on Biodiversity and Climate 

Change: Http://Www.Cbd.Int/Climate/Meetings/Ahteg-Bdcc-02-02/Ahteg-Bdcc-02-02-Findings-Review- 

En.Pd 

CEC (2007) Commission of the European Communities. Adapting To Climate Change In Europe – Options For EU 

Action. Green Paper from the Commission to the Council, the European Parliament, the European Economic 

and Social Committee and the Committee of the Regions. 29.6.2007 Com (2007) 354 Final {Sec(2007) 849}, 

Brussels 

Colacino M & Conte M. (1993a), Greenhouse effect and pressure patterns in the Mediterranean basin, Il Nuovo 

Cimento C 16, 67–76. 

Colacino M and Conte M (1993b) Clima mediterraneo ed incendi boschivi, Consiglio Nazionale delle 

Ricerche,Istituto di Fisica dell‘Atmosfera, Report 93-50. 

Colacino M & Conte M (1995) Heat Waves in the Central Mediterranean – a synoptic climatology. Nuovo Cimento 

Della Societa Italiana Di Fisica CGeophysicsand Space Physics 18, 295-304. 

Crosti R, Cascone C & Cipollaro S (2010) Use of a weed risk assessment for the Mediterranean region of Central 

Italy to prevent loss of functionality and biodiversity in agro-ecosystems. Biological Invasions 12, 1607- 

1616. 

EEA (2005) European Environment Outlook. EEA Report No 4/2005. 

Elith J & Leathwick JR (2009) Species distribution models: ecological explanation and prediction across space and 

time. Annual Review of Ecology Evolution and Systematics 40, 677–697. 

Fitzpatrick MC & Hargrove WW (2009) The projection of species distribution models and the problem of nonanalog 

climate. Biodiversity and Conservation 18, 2255–2261. 

Gao X & Giorgi F (2008) Increased aridity in the Mediterranean region under greenhouse gas forcing estimated 

from high resolution simulations with a regional climate model. Global and Planetary Change 62, 195–209. 

Gaucherel C, Guiot J & Misson L (2008) Changes of the potential distribution area of French Mediterranean forests 

under global warming. Biogeosciences 5, 1493–1504. 

Giannakopoulos C, Bindi M, Moriondo M, Lesager P & Tin T (2005) Climate Change Impacts in the 

Mediterranean resulting from a 2 o C global temperature rise. — A report for WWF. WWF, Gland. 

Giorgi F & Lionello P (2008) Climate change projections for the Mediterranean region. Global and Planetary 

Change 63, 90–104. 

Gran Canaria Group (2006) The Gran Canaria Declaration II on Climate Change and Plant Conservation. Cabildo 

de Gran Canaria, Jardìn Botánico ―Viera yClavijo‖ and Botanic Gardens Conservation International. 

Greuter W (1995) Extinctions in Mediterranean areas. In: Lawton JH & May RM (Eds.), Extinction Rates pp. 88– 

97. Oxford University Press, Oxford. 

Guisan A & Thuiller W (2005) Predicting species distribution: offering more than simple habitat models. Ecology 

Letters 8, 993-1009. 

Harding AE (2006) Changes in Mediterranean Climate Extremes: Patterns, Causes, and Impacts of Change. 

University of East Anglia PhD thesis, December 2006. http://www.cru.uea.ac.uk/cru/pubs/thesis/2006harding/ 

Heikkinen RK, Luoto M, Araújo MB, Virkkala R, Thuiller W. & Sykes MT (2006) Methods and uncertainties in 

bioclimatic envelope modelling under climate change. Progress in Physical Geography 30, 751 

Hellmann JJ, Byers JE, Bierwagen BG & Dukes JS (2008) Five potential consequences of climate change for 

invasive species. Conservation Biology 22, 534-43. 

Hertig E & Jacobeit J (2008) Downscaling Future Climate Change: Temperature Scenarios for the Mediterranean 

area. Global and Planetary Change 63, 127–131. 

Heywood VH (2010) The impacts of climate change on plant species in Europe. In: Biodiversity and climate 

change: Reports and guidance developed under the Bern Convention - Volume 2 (Nature and Environment 

NþXX). 

Higgins SI & Richardson DM (1999) Predicting plant migration rates in a changing world: The role of long-distance 

dispersal. American Naturalist 153, 464–475. 

Hoegh-Guldberg O, Hughes L, McIntyre S, Lindenmayer DB, Parmesan C, Possingham H P & Thomas CD (2008) 

Assisted colonization and rapid climate change. Science 321, 345–346. 



61

Hulme PE (2004) Islands, invasions and impacts: a Mediterranean perspective. In: Ecologìa insular/island ecology 

(Eds Fernández-Palacios, JM & Morici C) pp. 359–383. Asociaciñn Espaðola de Ecologia Terrestre (AEET), 

Cabildo Insular de La Palma. 

Hulme PE, Brundu C, Camarda I, Dalias P, Lambdon P, Lloret F, Medail, F, Moragues E, Suehs C, Traveset A, 

Troumbis A & Vilà M (2008) Assessing the risks to Mediterranean islands ecosystems from non-native plant 

introductions In: Plant invasions: human perception, ecological impacts and management (Eds ccTokarska- 

Guzik B, Brock JH, Brundu G, Child LE, Daehler C & Pysek P) pp. 39–56. Backhuys Publishers, Leiden, 

The Netherlands. 

Jeschke JM & Strayer DL (2008) Usefulness of bioclimatic models for studying climate change and invasive 

species. Annals New York Academy Sciences 1134, 1-24. 

Karas J (2000) Climate Change and the Mediterranean Region. Report foro Greenpeace 

http://archive.greenpeace.org/climate/science/reports/fulldesert.html 

Klausmeyer KR & Shaw MR (2009) Climate change, habitat loss, protected areas and the climate adaptation 

potential of species in mediterranean ecosystems worldwide. PLoS ONE 4, e6392. 

doi:10.1371/journal.pone.0006392 

van Kleunen M & Fischer M (2005) Constraints on the evolution of adaptive phenotypic plasticity in plants. New 

Phytologist 166, 49–60 

Lavorel S (1999) Ecological diversity and resilience of Mediterranean vegetation tio disturbance. Diversity and 

Distributions 5, 3–13. 

Linares JC & Tìscar PA (2010) Climate change impacts and vulnerability of the southern populations of Pinus nigra 

subsp. salzmannii. Tree Physiology 30, 795–806 

Lionello P, Platon S & Rodñ X (2008). Preface: Trends and climate change in the Mediterranean region. Global and 

Planetary Change 63, 87–89. 

Massot M, Clobert J & Ferrière R (2008) Climate warming, dispersal inhibition and extinction risk. Global Change 

Biology 14, 461–469. 

McGeoch MA, Butchart SHM, Spear D, Marais E, Kleynhans EJ, Symes A, Chanson J & Hoffmann M (2010) 

Global indicators of biological invasion: species numbers, biodiversity impact and policy responses. 

Diversity and Distributions 16, 95–108. 

Midgley GF, Thuiller W, & Higgins SI (2007) Plant species migration as a key uncertainty in predicting future 

impac ts of climate change on ecosystems: progress and challenges. In: Terrestrial Ecosystems in a Changing 

World, (Eds Canadell J, Pataki D & Pitelka L), pp. 129-137. Springer, New York 

MRFA (2009) A Mediterranean Forest Research Agenda – MRFA 2010–22020. European Forest Institute. 

Mediterraanean Regional Office – EFIMED, Barcelona. 

NAS (2002) National Research Council: Committee on the Scientific Basis for Predicting the Invasive Potential of 

Nonindigenous Plants and Plant Pests in the 

United States. 2002. Predicting Invasions of Nonindigenous Plants and Plant Pests. National Academy of Sciences, 

Washington DC. 

Naveh Z (1991)The role of fire in Mediterranean vegetation. Botanica Chronika (Greece) 10,385-405. 

Nix HA (1986) BIOCLIM — a Bioclimatic Analysis and Prediction System". Research report, CSIRO Division of 

Water and Land Resources 1983–1985, 59–60. 

Ortolani F & Pagliuca S (2006) Natural, Rapid and Cyclical Climatic-Environmental Change in the Mediterranean 

Area and Human Responses During the Last 3000 Years. In: Abstracts, Dark Nature - Rapid Natural 

Change and Human Responses, Como Meeting 2005. pp. 16–18. http://scienzecomo.uninsubria.it/ambientale/sitodn/index.html 

(accesssed 2 July 2010) 

Palahi M, Mavsar R, Gracia C & Birot Y (2008) Mediterranean forests under focus International Forestry Review 

10, 676–688. 

Paun O, Bateman RM, Fay M , Hedren M, Civeyrel L & Chase MW (2010) Stable epigenetic effects impact 

adaptation in allopolyploid orchids (Dactylorhiza: Orchidaceae). Molecular Biology and Evolution 20 

Doi:10.1093/molbev/msq150 

Pausas JG (1999) Mediterranean vegetation dynamics: modelling problems and functional types. Plant Ecology 140, 

27–39. 

Pearson TG & Dawson TP (2005) Long-distance plant dispersal and habitat fragmentation: identifying conservation 

targets for spatial landscape planning under climate change. Biological Conservation 123, 389–401. 

Peðuelas J & Boada M (2003) A global change-induced biome shift in the Montseny mountains NE Spain. Global 

Change Biology 9, 131–140. 



62

Peterson AT, Stewart A, Mohamed K & Araújo MB (2008) Shifting Global Invasive Potential of European Plants 

with Climate Change. PLoS ONE 3(6), e2441. doi:10.1371 

Pyšek P, Jarošik V, Hulme PE, Kühn I, Wild J, Arianoutsou M, Bacher S, Chiron F, Didţiulis V , Essl F, Genovesi 

P, Gherardil F, Hejda M, Kark S, Lambdon PW, Desprez-Loustau M-L, Nentwig W, Pergl J, Poboljšaj K, 

Rabitschj W, Roques A,. Roy DB, Shirley S, Solarz W, Vilà M & Winter M (2010) Disentangling the role of 

environmental and human pressures on biological invasions. Proceedings of the National Academy of 

Sciences USA doi: 10.1073/pnas.1002314107 

Quézel P & Médail F (2003) Ecologie et biogeography des forêts du bassin Méditerranéen. Collection 

Environnement. Elsevier, Paris. 

Regato P (2008) Adapting to global change: Mediterranean forests. IUCN Centre for Mediterranean Cooperation, 

Malaga. 

Reichard SH & White P (2001) Horticulture as a pathway of invasive plant introductions in the United States. 

BioScience 51, 1103–113. 

Resco de Dios V, Fischer C & Colinas C (2007) Climate change effects on mediterranean forests and preventive 

measures. New Forests 33, 29–40 

Richards CL, Bossdorf O & Pigliucci M (2010a) What role does heritable epigenetic variation play in phenotypic 

evolution? Bioscience 50, 232–237. 

Richards CL, Bossdorf O & Verhoeven KJF (2010b).Understanding natural epigenetic variation. New Phytologist 

187, 562–564. 

Robinson DCE, Beukema SJ & Greig LA (2008) Vegetation models and climate change: workshop results. 

Prepared by ESSA Technologies Ltd., for Western Wildlands Environmental Threat Assessment Center, 

USDA Forest Service, Prineville, OR. 

Sanz Elorza M, Dana DD, Sobrino Vesperinas E (2004) Atlas de Plantas Alóctonas invasoras en España. Direcciñn 

General para la Bioversidad, Madrid 

Schröter D, Cramer W, Leemans R., Prentice IC, Araújo MB, Arnell N, Bondeau, A, Bugmann H, Carter TR, 

Gracia CA, De La Vega-Leinert AC, Erhard M, Ewert F, Glendining M, House JI, Kankaanpää S, Klein 

RJT, Lavorel S, Lindner, M, Metzger MJ, Meyer J, Mitchell TD, Reginster I, Rounsevell M, Sabaté S, Sitch 

S, Smith B, Smith J, Smith P, Sykes MT, Thonicke K, Thuiller W, Tuck G, Zaehle S & Zierl B (2005) 

Ecosystem Service Supply and Vulnerability to Global Change in Europe. Science 310, 1333–1337. 

Sinclair SJ, White MD & Newell GR (2010) How useful are species distribution models for managing biodiversity 

under future climates? Ecology and Society 15(1), 8. [online] URL: 

http://www.ecologyandsociety.org/vol15/iss1/art8/ 

Thuiller, W, Lavorel S, Araújo MB, Sykes MT & Prentice, IC (2005) Climate change threats plant diversity in 

Europe. Proceedings of the National Academy of Sciences USA 10, 8245-8250. 

Thuiller W, Albert C,. Araújo MB, Berry PM, Guisan A, Hickler T, Midgley GF, Paterson,J, Schurr FM, Sykes MT 

& Zimmermann NE (2008) Predicting climate change impacts on plant diversity: where to go from here? 

Perspectives in Plant Ecology, Evolution and Systematics 9, 137–152. 

Traveset A, Brundu G, Carta M, Mprezetou I, Lambdon P, Manca M, Me´dail F, Moragues E, Rodriguez-Perez J, 

Siamantziouras S, Suehs CM, Troumbis A, Vila` M, Hulme PE (2008) Consistent performance of invasive 

plant species within and among islands of the Mediterranean basin. Biological Invasions 10, 847–858 

Valladares F, Gianoli E & Gñmez JM (2007) Ecological limits to plant phenotypic plasticity. New Phytologist 176: 

749–763. 

Vilà M, Corbin JD, Dukes JS, Pino J & Smith SD (2007) Linking plant invasions to global environmental change. 

In: Terrestrial Ecosystems in a Changing World (Eds Canadell J, Pataki D & Pitelka L), pp. 93-102. 

Springer, New York 

Willis KJ & Bhagwat SA (2009) Biodiversity and climate change. Science 326, 806–807. 

WTO (2003) Tourism Market Trends, 2003 Edition, World Tourism Organization, Madrid. 



63

Flora of Turkey: Richness, updates, threats 

Necmi Aksoy 

Düzce University Forest Faculty, Department of Forest Botany & DUOF Herbarium, 

Beçiyörükler, Düzce, Turkey, E-mail: necmiaksoy@duzce.edu.tr 

The flora of Turkey is rich and diverse with over 11 000 flowering taxa recorded in the 9-volume 

set of Prof. P.H. Davis‘ monumental work and its two supplements. Turkey is situated at the 

junction of three important phytogeographic regions, namely Mediterranean, Irano-Turanian, and 

Euro-Siberian. The Black Sea‘s coastal areas are in the Euro-Siberian region. Areas surrounding 

the Mediterranean, Aegean, and Marmara Seas enjoy the characteristics of the Mediterranean 

regions, and finally, the large part of Turkey stretching from the Central Anatolian Plateau to the 

borders with Iran and Iraq to the East and Southeast lies in the Irano-Turanian region. Endemic 

species are largely found in the Mediterranean and Irano-Turanian regions. The Anatolian flora, 

especially in the steppe areas, is said to be in an active state of diversification. According to the 

Flora of Turkey, the flora contains just over 11000 infrageneric taxa, of which 34.5 % are 

endemic. In the flora of Turkey, percentage endemism is high in some families: Boraginaceae 

(61%), Campanulaceae (60%), Scrophulariaceae (52%), Rubiaceae (48%), Caryophyllaceae 

(46%), Labiatae (45%), Leguminosae (40%), Compositae (37%). At generic level, examples of 

the rate of endemism are: Bolanthus (90%), Ebenus (90%), Alkanna (8l%), Sideritis (78%), 

Acantholimon (76%), Paronychia (75%), Verbascum and Gypsophila (71%), Paracaryum 

(70%), Cousinia (68%), Centaurea (65%), Astragalus (63%). The flora of Turkey contains over 

11 000 vascular plant taxa, a considerable number of which are used by humans. Non-food uses 

of plants include medicinal, aromatic, ornamental, pesticides as well as raw materials for making 

household goods, toys, musical instruments. The flora of Turkey is estimated to contain over 

3000 aromatic plants. The wide biodiversity of the flowering plants of Turkey is reflected in the 

11-volume set of books titled Flora of Turkey and the East Aegean Islands. The second 

supplement (Vol. 11) reported 532 new taxa for the flora of the region. Recently, publications 

reported that 48 new recorded and 135 new species are added to the Flora of Turkey and the 

following genus were recently included : Clastopus, Adenostyles, Araujia, Perilla, Oreopoa, 

Diplachne, Asperuginoides, Leptaleum, Stroganowia, Loncomelos, Scopolia, Oclopoa, 

Chamaespartium, Lophanthus, Clerodendrum, Cymbopogon , Schistophyllidium, Sicyos, etc. If 

the alien and cultivated taxa are included, the number of taxa occurring in the Flora of Turkey 

then rises to 11 500. Of 3504 endemic plants in Turkey, 12 are known to have been extinct and 

3492 (99 %) are still being threatened. The main threats to the survival of Turkey‘s endemic 

plants are: clearing grounds for fields, overgrazing and reform of barren lands, construction of 

dams, industrialization and urbanization, exportation and domestic use, plant protection and 

pollution, tourism, forestation and fires. 



64

Role of soil communities and novel weapons in exotic plant invasion: an update 

Inderjit 

Department of Environmental Biology, 2 Centre for Environmental Management of Degraded 

Ecosystems (CEMDE), University of Delhi, Delhi 110007, India, Emails: 

inderjit@cemde.du.ac.in; inderjitdu@gmail.com 

Introduction 

A large number of empirical studies are carried out to understand why some 

exotic plants often form monocultures and suppress native residents while they 

coexist in species-diverse communities in their native area. Here some recent 

studies that support the interaction of chemicals produced by exotic plants and 

soil communities in plant invasions are discussed. There is a need to 

understand the ‗expanded‘ effects of novel chemicals; for example, novel 

chemicals-microbial interactions in the non-native ranges that benefit the donor 

plant and thereby harm the neighbouring plant species. 

A question that fascinates most ecologists is why some exotic plants form monocultures in 

non-native ranges and suppress their neighbours while they coexist in species-diverse 

communities in their native range (Callaway et al., 2008; Ridenour et al., 2008). A large number 

of non-exclusive hypotheses have been proposed to explain invasion success of exotic plants in 

their non-native ranges (Inderjit et al., 2005; Catford et al., 2009). Any discussion on each of the 

proposed hypotheses is beyond the scope of this article. Recent empirical work has generated 

some convincing evidence in support of evolution of increased competitive ability (Handley et 

al. 2008; Hull-Sanders et al., 2007; Feng et al., 2009), endophyte-mediated alteration of soil 

biota (Rudgers & Clay 2007; Rudgers & Orr 2009), accumulation of soil pathogens (Eppinga et 

al., 2006; Mangla et al., 2008), impact of local soil communities (Inderjit & van der Putten 2010; 

Scharfy et al., 2010), novel weapons (Inderjit et al., 2006; He et al., 2009; Thorpe et al., 2009), 

and improved our understanding of biological invasions. Below I discuss novel chemicals, soil 

communities, and evolution of increased competitive ability in order to highlight their 

contribution to exotic plant invasion. 

Evolution of increased competitive ability (EICA) and novel chemicals 

Exotic plants upon introduction are either partially (enemy reduction; Beckstead and Parker 

2003) or completely (enemy release; Keane & Crawley, 2002) released from specialist enemies. 

Müller-Schärer et al. (2004) described enemy release process as regulatory or compensatory. 

When a plant has low resistance to specialist enemies in its native range, the loss of its enemies 

in the introduced range results in direct survivorship; in this case the release is called regulatory 

release. On the other hand, when the plant in its native range is well defended against specialist 

enemies by producing defense metabolites, the loss of enemies in non-native ranges would have 

little consequences to the plant; in this case the release is called compensatory release. Resource 

allocation of the exotic plant to quantitative defense is expensive, however, plants could evolve 



65

to reallocate for better growth and competitive ability. This mechanism is known as the evolution 

of increased competitive ability (EICA; Blossey & Notzhold, 1995). 

Plants are known to release chemicals in the environment that could suppress growth and 

establishment of neighboring plants (allelopathy). Callaway & Ridenour (2004) examined 

allelopathy as one of the potential causes of invasion success of exotic plants by taking a 

biogeographically approach, and termed it as the Novel Weapons Hypothesis (NWH). In this 

biogeographically approach, the allelopathic potential of the plant in its native range is compared 

with that they express in the non-native range (Inderjit et al., 2008). Compared to traditional 

approach to study allelopathy, biogeographically approach considers the possibility of the 

evolution of allelopathy (Inderjit et al., 2008). Novel weapons hypothesis has a strong support on 

the evidences that the general effects of Eurasian invader Centaurea maculosa, and chemicals 

contained in its roots exudates, were more effective against species in invaded region (North 

America) than in native regions (Callaway & Ridenour, 2004). The major assumption of NWH is 

that native species are not adapted to novel chemicals brought to non-native range by exotic 

plants, which is further supported by Grøndahl & Ehlers (2008). These authors studied the 

effects of 2 terpenes, carvacrol and β-caryolphyllene produced by Tyhmus pulegiodes and T. 

serpyllum on the growth of neighbouring plant species. In general, local species showed 

adaptation to these chemicals in the native range and therefore are not sensitive to chemicals and 

have potential to break down chemicals released by the plant. 

One of the major criticisms of allelopathy is the lack of field evidence (Inderjit & Weiner, 

2001; Inderjit & Callaway, 2003). However, novel weapons hypothesis, however, provide 

convincing field evidence in the support of novel chemicals playing an important role in invasion 

success of an exotic plant (see Thorpe et al., 2009; He et al., 2009; Barto et al., 2010a). 

Allelopathy hypothesis is suggested as a sub-set of the EICA hypothesis (Callaway & 

Ridenour, 2004; Inderjit et al., 2006) because novel chemicals in the non-native range provide 

competitive advantage to the exotic plant over the native ones. Callaway & Ridenour (2004) 

proposed that selection for greater allelopathic output could be an alternative mechanism for the 

evolution of the increased competitive ability and coined this hypothesis the allelopathic 

advantage against resident species. These authors speculated that higher allelopathic potential of 

invaders compared to their native populations could be due to production of higher amounts of 

potent chemicals and due to sensitive neighbours and soil communities. 

Müller-Schärer et al. (2004) viewed that invaders generally have not completely escaped from 

their enemies, and proposed to revise EICA hypothesis to include the role of generalist 

herbivores. It is important to conduct a rigorous re-examination of C. maculosa invasion in the 

light of the refined EICA hypothesis proposed by Müller-Schärer et al. (2004), comparing levels 

of herbivory by generalist and specialist herbivores in the invaded and native range. While 

examining trade-offs between growth and defense, Ridenour et al. (2008) showed that plants of 

N. American C.maculosa were larger than plants from native European populations, which 

supports the EICA hypothesis. However, N. American C. maculosa were better defended against 

generalist in terms of better resistance and tolerance because invasive populations had tough 

leaves and more trichomes. Their study showed that EICA may not always lead to trade-offs 

between growth and defense. 

66 



Recently, Feng et al. (2009) examined the reallocation of nitrogen (N) from defense to growth 

in the invaded ranges of the Ageratina adenophora, a Mexican invader in China and India. Seeds 

of A. adenophorafrom the native (Mexico) and non-native (China and India) ranges were 

collected and grown in common-garden experiments. It was found that A. adenophora in nonnatives 

ranges allocates N to growth but in its native ranges, it allocates Nitrogen to cell wall in 

order to have better defenses. Moreover, the higher growth rate of this plant in its non-native 

ranges compared to its native range, is an evidence supporting the EICA. The examination of a 

presumed increase in chemicals products in the non-native range was not studied for A. 

adenophora. 

Toxicity mediated by novel environment 

The role of novel chemicals in suppressing native resident plants in the non-native range of 

exotic plants is well discussed in literature but the role of native communities (plants and 

microbes) in contributing to the allelopathic potential of an exotic plant is not discussed. Exotic 

plants may bring chemicals that do not exert any toxicity against neighboring plants but native 

plants and soil communities of the non-native range may transform innocuous novel compounds 

to toxic compounds. Recently, Bains et al. (2009) have shown that Phragmites australis, an 

exotic invasive plant in marsh communities in North America, produces higher quantities of 

gallotannins compared to native, non-invasive populations. These authors have demonstrated 

that the enzyme tannase produced by native plants and microorganisms have the property to 

transform innocuous gallotannins into gallic acid, a toxic compound. This is a good example 

showing the participation of native plants and soil communities in producing novel chemicals 

which in turn contributed to the invasive success of P. australis. 

Invasion mediated by soil microbes 

Recently, Inderjit & van der Putten (2010) discussed the effects of soil microbial communities 

on exotic plant invasion and the impact of exotic plant invasion on soil communities as well. In 

addition to the potential of exotic plants to escape soil pathogens (Klironomos 2002) and positive 

(Callaway et al., 2004) or negative (Knevel et al., 2004) impacts of soil communities on exotic 

plants, exotic plant could accumulate soil biota that suppress the seedlings of neighboring plant 

species. While working on the invasion success of Chromolaena odorata, a native of Caribbean 

and an aggressive invasive weed in the Western Ghats of India, Mangla et al. (2008) has found 

that rhizosphere soils of C. odorata accumulate high concentrations of a local soil pathogen, 

which creates a negative impact on the seedlings of native plants. These results support an earlier 

general hypothesis proposed by Eppinga et al. (2006), a hypothesis known as accumulation of 

soil pathogens. Whether chemicals exuded by roots of C. odorata favors the accumulation of soil 

pathogen is not proven experimentlly. Mangla et al. (2008), however, provided some indirect 

evidence that root leachates of C. odorata promotes higher number of spores of soil pathogens. 

The negative impacts of L. arundinaceum on native plant species are mediated through a 

aboveground fungal endophyte, Neotyphodium coenphialum present in the non-native grass 

Loilium arundinaceum (Rudgers & Orr, 2009; Rudgers et al., 2004). By altering soil biota, 

endophyte in L. arundinaceum exerts negative impacts on tree species such as Elaeagnus 

umbellata, Fraxinus pennsylvanica and Platanus occidentalis. Rudgers & Orr (2009) highlighted 

67 



the importance of above- and belowground microbial communities in providing competitive 

advantage to the non-native grass, L. arundinaceum. 

Callaway et al. (2008) reported that Alliaria petiolata, an eurasian invader from N. American 

forests, disrupt the mutualistic associations between arbuscular mycorrhizal fungi (AMF) and 

tree species. These authors found that A. petiolata when was present in N. American soils had 

negative impact on AMF and the regeneration of native mycorrhizal tree seedlings. Such effects 

were not observed when A. petiolata grown in native European soils. In contrast, Barto & 

Cipollini (2010b) found that A. petiolata extract had no impact on AMF colonization of roots or 

soils, and suggested that potential alleopathic effects of A. petiolata could be due to direct 

inhibition of plant seedlings and fungus before the formation of symbiosis. 

Concluding remarks 

Callaway and his co-workers have proposed the biogeographically approach to examine the 

dimension in allelopathic studies. This approach has contributed to a better understanding about 

the ecological and evolutionary aspects of allelopathy in the context of plant invasion ecology. 

Lankau (2009) examined the glucosinolate content in the Alliaria petiolata of different invasion 

history in N. America. He observed a significant decline in the production of glucosinolates from 

A. petiolata over a span of more than 50 years from its invasion, which resulted in the decline of 

the invasiveness of this invasive plant in N. American forests. Recent studies have shown that 

enemy release, EICA, plant-soil feedback and novel weapons interact with each other in a 

complex way (Feng et al., 2009; Inderjit and van der Putten 2010). Moreover, in allelopathy 

studies, the importance of microbial interactions is underemphasized (see Kaur et al., 2009). In 

this vein, the scope of novel chemicals/allelopathy should be broadening to identify the 

chemical-microbial interactions that benefit the focal exotic plant and thereby suppress 

neighboring native plant species. 

Other factors such as propagule pressure could bean important factor that can be consistently 

correlated to the invasive success (Lockwood et al., 2005). Massive seed production appeared to 

be a requirement for dominance, and in the absence of a massive seedbank, even competition 

that is potentially assisted by allelopathic chemicals, is inadequate to maintain the dominance of 

this species. It is important to examine the ways an exotic plant multiplies in the non-native 

ranges, its potential to take advantage of new resources and conditions compared to local species 

and its potential to manipulate abiotic and biotic soil factors. 

Acknowledgements 

This paper was presented at the 2nd International Workshop on Invasive Alien Plants in the 

Mediterranean Type of Regions of the World, Trabzon, Turkey, August 2010. I thank Ahmet 

Uludag and Sarah Brunel to invite me to the workshop. Funding provided by the European 

Environment Agency (EEA) is gratefully acknowledged. 

References 

Bains G, Kumar AS, Rudrappa T, Alff E, Hanson TE & Bais HP (2009) Native plant and microbial contributions to 

a negative plant-plant interaction. Plant Physiology 151, 2145-2151. 



68

Barto K, Powell JR & Cipollini D (2010a) How novel are the chemical weapons of garlic mustard in North America 

forest understories. Biological Invasions 12, 3465-3471. 

Barto K, Friese C & Cipollini D (2010b) Arbuscular mycorrhizal fungi protect a native plant from allelopathic 

effects of an invader. Journal of Chemical Ecology 36, 351-360. 

Beckstead J & Parker IM (2003) Invasiveness of Ammophila arenaria : release from soil-borne pathogens? Ecology 

84, 2824-2831. 

Blossey B & Notzgold R (1995) Evolution of increased competitive ability in invasive non-indigenous plants: a 

hypothesis. Journal of Ecology 83, 887-889. 

Callaway RM & Ridenour WM (2004) Novel weapons: invasive success and the evolution of increased competitive 

ability. Frontiers in Ecology and the Environment 2, 436-443. 

Callaway RM, Cipollini D, Barto K, Thelen GC, Hallett SG, Prati D, Stinson K & Klironomos J (2008) Novel 

weapons: invasive plant suppresses fungal mutualists in America but not in its native Europe. Ecology 89, 

1043-1055. 

Callaway RM, Thelen GC, Rodriguez A & Holben WE (2004) Soil biota and exotic plant invasion. Nature 427, 

731-733. 

Catford JA, Jansson R & Nilsson C (2009) Reducing redundancy in invasion ecology by integrating hypotheses into 

a single theoretical framework. Diversity & Distribution 15, 22-40. 

Eppinga MB, Rietkerk M, Dekker SC, Ruiter PC & van der Putten WH (2006) Accumulation of local pathogens: a 

new hypothesis to explain exotic plant invasions. Oikos 114, 168-176. 

Feng YL, Lei Y, Wang R, Callaway RM, Valiente-Banuet A, Inderjit, Li Y-P & Zheng Y-L (2009) Evolutionary 

tradeoffs for nitrogen allocation to photosynthesis versus cell walls in an invasive plant. Proceedings 

National Academy of Sciences U.S.A. 106, 1853-1856. 

Grøndahl E & Ehlers BK (2008) Local adaptation to biotic factors: reciprocal transplants of four species associated 

with aromatic Thymus pulegiodes and T. serpyllum. Journal of Ecology 96, 981-992. 

Handley RJ, Steinger T, Trier UA & Muller-Scharer H (2008) Testing the evolution of increased competitive ability 

(EICA) hypothesis in a novel framework. Ecology 89, 407-417. 

He WM, Feng Y, Ridenour W, Thelen GC, Pollock JL, Diaconu A, Callaway RM (2009) Novel weapons and 

invasions: biogeographic differences in the competitive effects of Centaurea maculosa and its root exudates 

(±)-catechin. Oecologia 159, 803-815. 

Hull-Sanders HM, Clare R, Johnson RH & Meyer GA (2007) Evaluation of the evolution of increased competitive 

ability (EICA) hypothesis: loss of defense against generalist but not specialist herbivores. Journal of 

Chemical Ecology 33, 781-799. 

Inderjit & Van der Putten WH (2010) Impacts of soil microbial communities on exotic plant invasion. Trends in 

Ecology and Evolution 25, 512-519. 

Inderjit & Callaway RM ( 2003) Experimental designs for the study of allelopathy. Plant and Soil 256, 1-11. 

Inderjit & Weiner J (2001) Plant allelochemical interference or soil chemical ecology? Perspectives in Plant 

Ecology, Evolution & Systematics 4, 3-12. 

Inderjit, Callaway RM & Vivanco JM (2006) Plant biochemistry helps to understand invasion ecology. Trends in 

Plant Science 11, 574-580. 

Inderjit, Seastedt TR, Callaway RM, Pollock J & Kaur J (2008) Allelopathy and plant invasions: traditional, 

congeneric, and biogeographical approaches. Biological Invasions 10, 875-890. 

Inderjit, Cadotte M & Colautti RI (2005) The ecology of biological invasions: past, present and future.Invasive 

Plants: Ecological and Agricultural Aspects (ed Inderjit), pp. 19-44. Birkhauser-Verlag AG, Basel 

(Switzerland). 

Kaur H, Kaur R, Kaur S, Baldwin IT & Inderjit (2009) Taking ecological function seriously: soil microbial 

communities can obviate allelopathic effects of released metabolites. PLoS One 4(3), e4700. 

doi:10.1371/journal.pone.0004700 

Keane RM & Crawley MJ (2002) Exotic plant invasions and the enemy release hypothesis. Trends in Ecology and 

Evolution 17, 164-70. 

Klironomos J (2002) Feedback with soil biota contributes to plant rarity and invasiveness in communities. Nature 

417, 67-70. 

Knevel IC, Lans T, Menting FBJ, Hertling UM & Van der Putten WH (2004) Release from native root herbivores 

and biotic resistance by soil pathogens in a new habitat both affect the alien Ammophila arenaria in South 

Africa. Oecologia 141, 502-510. 



69

Lankau RA, Nuzzo V, Spyreas G & Davis AS (2009) Evolutionary limits ameliorate the negative impacts of an 

invasive plant. Proceedings of the National Academy of Sciences USA 106, 15362-15367. 

Lockwood JL, Cassey P & Blackburn TM (2005) The role of propagulepressure in explaining species invasion. 

Trends in Ecology and Evolution 20, 223-228. 

Mangla S, Inderjit & Callaway RM (2008) Exotic invasive plant accumulates native soil pathogen which inhibit 

native plants. Journal of Ecology 96, 58-67. 

Müller-Schärer H, Schaffner U & Steinger T (2004) Evolution in invasive plants and implications for biological 

control. Trends in Ecology and Evolution 19, 417-422. 

Ridenour WM, Vivanco JM, Feng Y, Horiuchi J & Callaway RM (2008) No evidence for trade-offs: Centaurea 

plants from America are better competitors and defenders. Ecological Monographs 78, 369-386. 

Rudgers JA & Orr S (2009) Non-native grass alters growth of native species via leaf and soil microbes. Journal of 

Ecology 97, 247-255. 

Rudgers JA, Koslow JM & Clay K (2004) Endophytic fungi alter relationships between diversity and ecosystem 

properties. Ecology Letters 7, 42-51. 

Rudgers JA & Clay K (2007) Endophyte symbiosis with tall fescue: how strong are the impacts on communities and 

ecosystems? Fungal Biology Reviews 21, 107-124. 

Scharfy D, Gusewell S, Gessner MO & Venterink HO (2010) Invasion of Solidao gigantean in contrasting 

experimental plant communities: effects on soil microbes, nutrients and plant-soil feedbacks. Journal of 

Ecology 98, 1379-1388. 

Thorpe AS, Thelen GC, Diaconu A & Callaway RM (2009) Root exudate is allelopathic in invaded community but 

not in native community: field evidence for the novel weapons hypothesis. Journal of Ecology 97, 641-645. 



70

Invasive weed threats in Gangetic inceptisol of India and their management 

R. K.Ghosh, FAPS, FISWS 

Department of Agronomy, Faculty of Agriculture, Bidhan Chandra Krishi Viswavidyalaya, 

(BCKV)Mohanpur-741252, West Bengal, India, Email: rajbckv@rediffmail.com 

Climate change and the import of foodgrains & seeds are the two major causes 

for the invasion of the many weeds in the Gangetic Inceptisol of India. Holding 

2.4% Worlds‘ land area and 10 Bio geographical zones, India has 8% of 

worlds‘ biodiversity and is 10th among plant rich nations of the World (4th 

among Countries of Asia). India has 42 Vegetation types, 16 major Forest 

types, approximately 126,188 species covering all 5 Kingdoms including 9000 

higher plant species (flowering plants are 17,000 species). In recent decades 

the reduction in India‘s plant species is approximately 10 % in flowering plants 

including more than 150 Medicinal plants. More than 32 weed pests have 

invaded since the mid 1990s via the import of seed. In India production losses 

due to pests is 33% and out of this, the major pest weed plant alone causes 37% 

yield losses. Management of these invasive weed pests is therefore urgently 

needed in addition to proper management of soil and water resources to 

increase the food production for India‘s food security. 

Survey & Surveillance under the National Weed Surveillance Programme, 

Ministry of Agriculture, Government of India revealed that in the anaerobic 

ecosystems (puddle condition, semi aquatic and aquatic situation) Eichhornia 

crassipes, Oryza rufipogon, Aneilema vaginata, Panicum repens, Eriocaulon 

sieboldtianum, Eleocharis congesta, Fimbristylis dichotoma, Scirpus 

mucronatus, Cyperus microiria, Cyperus serotinus, Cyperus polystschyos, 

Cyperus fulvo-albescens, Alternanthera philoxeroides etc. and in aerobic 

ecosystems (no water stagnation condition) Elatine triandra, Phalaris minor, 

Tithonia rotundifolia, Cynoglossum germinacum, Polygonum plebium, 

Desmodium triflorum, Trichodesma indicum, Euphorbia heleoscopia, 

Euphorbia heterophylla, Cardenthera triflora etc. are common invasive weeds. 

In the non-crop areas, roadsides & wasteland ecosystems Parthenium 

hysterophorus, Cleome rufidosperma, Solanum incanum, Pergularia daemia, 

Rouvolfia tetraphylla, Hibiscus subdarifa, Acanthus ilicifolius, Desmodium 

laxiflorum, Solanum viarum, Solanum miriacanthum, Solanum indisanum, 

Solanum diphyllum, Miscanthus sacchariflorus etc. have also invaded, some of 

them now entering crop fields. During 2007-08 five more invasive weeds 

Cenchrus tribuloides, Ambrosia trifida, Viola arvensis, Cynoglossum officinale 

and Solanum carolinenses have entered in India with imported wheat food 

grains. 

Research on biology of these invasive weeds during the past decade showed 

the possibilities for their management. Utilizing this invasive weed flora in 

various agricultural and social purposes including compost making, 

biopesticides, biogas, biofuel, herbal technology etc. that create employment 

are so far identified as the best measure in addition to usually applied chemical 

71 



Introduction 

or physical method of weed control. Awareness through public participation 

including the farmers is the most common strategy for tackling these alien 

invasive weed pests. 

The population of India is estimated to reach 1.2 billion during 2011; 17.7 % more than that of 

2001 and the National foodgrains demand based on medium dietary requirement is also 

estimated as 253 mt. The food production in 2009-10 was only 219.2 mt (ICAR, 2010). 

Therefore, within just one year 33 mt more production is an arduous task. In such situation the 

‗System of Intensification’ or the unique Best Management Practice (BMP) where ‗Rainbow 

Revolution‘ is followed with the advance bio-products and available resources based technology 

combining with the wisdom of the age old practices of the art of cultivation (ITK) is the best 

alternative methodology. The major four components of this technology are Management of 

improved Seed; Management of Nutrients; Management of Water & Management of Pest in 

integrated approaches giving priority to Weed Management, and to the major pests causing 

maximum losses (Ghosh et. al., 2009). 

In the management of improved seed (meaning more than 99 % germination capability, viable 

and pure seed) climate change and the import of food grains and seeds are the two major causes 

for the invasion of many alien plants or pests. The numbers of days of more than 12 mm rainfall 

have decreased by 78 per cent in the last 53 years (Current Science, August 25, 2005, scientific 

article of PV Joseph, scientist at the Cochin University of Science and Technology).Weed 

Species of Quarantine Significance to India according to special provisions for Quarantine weeds 

[class 3(12)] & Schedule VIII of Plant Quarantine order 2005 showed that already 33 weed 

species were invaded India (DWSR, 2010). Further Survey & Surveillance under the National 

Weed Surveillance Programme, Ministry of Agriculture, Government of India (2007-08-2009- 

10) revealed that in the anaerobic ecosystems Eichhornia crassipes, Oryza rufipogon, Aneilema 

vaginata, Panicum repens, Eriocaulon sieboldtianum, Eleocharis congesta, Fimbristylis 

dichotoma, Scirpus mucronatus, Cyperus microiria, Cyperus serotinus, Cyperus polystschyos, 

Cyperus fulvo-albescens, Alternanthera philoxeroides etc. and in aerobic ecosystems Elatine 

triandra, Phalaris minor, Tithonia rotundifolia, Cynoglossum germinacum, Polygonum plebium, 

Desmodium triflorum, Trichodesma indicum, Euphorbia heleoscopia, Euphorbia heterophylla, 

Cardenthera triflora etc. are common invasive weeds. In the non-crop areas, roadsides & 

wasteland ecosystems Parthenium hysterophorus, Cleome rufidosperma, Solanum incanum, 

Pergularia daemia, Rouvolfia tetraphylla, Hibiscus subdarifa, Acanthus ilicifolius, Desmodium 

laxiflorum, Solanum viarum, Solanum miriacanthum, Solanum indisanum, Solanum diphyllum, 

Miscanthus sacchariflorus etc. have also invaded and some of them are now entering the crop 

fields. During 2007-08, five more invasive weeds Cenchrus tribuloides, Ambrosia trifida, Viola 

arvensis, Cynoglossum officinale and Solanum carolinenses have entered India with imported 

wheat food grains (Annual Report, NIWS, BCKV Centre, 2009-10). The production as well as 

social losses caused by these invasive weed plants is gradually increasing. Therefore, managing 

these weed plants is an urgent need for the food security in the world (DWSR, 2009). 



72

Ecology and biology of invasive weed plants 

The biology studies of some of the invasive weed plants revealed that grain setting in 

Gangetic inceptisol of Oryza rufipogon is only during June sowing. Phalaris minor in winter is 

now distributed from wheat field to road side in the North-West of India and also invades 

Eastern India. Solanum carolinense was found in Southern India during 2009 (Annual Report, 

NIWS, Bangalaru & Tamil Nadu Centre, 2009). 

Most of these invasive weed plants contain allelochemicals which may be utilized as 

biopesticides. Some of these chemicals were already isolated such as Benzoic acid; Cinnamic 

acid, Phenolic acid, Cumarins, Hydroquinones, Cineoles, Alkaloides, Tannins, Benzoquinones, 

Thiopenes, Juglone, Gallic acid Dhurin, Oxalates, Glocosides, Trymethyl xanthene, Prussic acid, 

etc. 

Calotropis gigantea and Calotropis procera are two very common species of Rooster tree. 

These are generally found along the roadsides and locally known as Akanda, Mandara, 

Vellerukka or Ark. These shrubs are also wasteland weeds. Calotropis gigantea is bigger than 

Calotropis procera. The leaves are simple, opposite, sub-sessile, oblong and acute. Flowers are 

pink, spotted with purple, buds globose, corolla scales with purple, seeds broadly ovate, 

flattened, comose (Naidu et al., 2005). This Swallo-wort plant is commonly propagated by seeds 

which are broadly ovate flattened with silky hairs at the apex, light brown in color and slightly 

reticulate. 

Parthenium hysterophorous is an invasive weed commonly found along roadsides. It is 

locally known as Congress grass. It was first found at Pune, India in 1955 and in 1975 at 

Dankuni, West Bengal. It is now covering 35 m ha in India (DWSR 2010) and has been termed 

‗National weed‘ since 2005-06. It enters crop fields from the roadsides. It is a shrub, commonly 

completing three life cycles in one year in this region (February, June and October). The plant 

mainly propagates by seeds. One plant contains 15,000-25,000 seeds which are very light and 

easily dispersed by air and water. It grows well in moist conditions but cannot tolerate water 

stagnation. It is very difficult to control unless at a time the eradication of this weed plant is done 

in all places of a region. The pollen allelopathy, a rare phenomenon inhibiting the germination of 

the pollen of other species in their respective stigma shown by Parthenium pollen may result in 

yield loss of crops.. It is reported for out burst of the diseases like tomato leaf curl, bud necrosis 

of groundnut and sunflower, stem necrosis of groundnut, powdery mildew, collar rot, leaf spot, 

milly bug and rust of various crops. Recently, Parthenium has been responsible for out burst of 

bud necrosis of groundnut in Andhra Pradesh and some parts of Karnataka. In India, it is 

estimated to lower the yield of field crops by 40% and forage crops by 90% in severely infested 

areas. In Australia, its damage is put at 16 million dollars per annum from pasture and crops. 

Pollen grains of Parthenium are reported to inhibit fruit set in tomato, bringal, beans, capsicum 

and maize (DWSR, 2010; Ghosh et al., 2009). Parthenium is also causing health hazards to 

human and animals 



73

Management of invasive weed plants 

Research on the management of these invasive weeds revealed that Calotropis plant is used as 

green manure and for fibre making. Calotropis latex is used for curing swellings and pain. The 

juice contains Mudarine used as purgative (Ghosh et al., 2007). Calotropin, the extract of roots is 

also used for fertility control in plants (Naidu et al., 2005). The tribal peoples of Medinipur are 

using the extracts of Calotropis against scabis and antifungal by mixing with mustard oil and 

extracts of Heliotropium indicum (Ghosh et al., 2008). The Calotropis raw leaf and stem extracts 

has been used as herbicide and it has been found that the raw extract applied at 5 ml/ litre of 

water as pre emergence in Soybean (Ghosh, 2008) and also in Paddy found useful to control 

grass and broadleaves categories of weeds (Adhoc project under Rastrya Krishi Bikash Yajana, 

2010). 

Young non-flowered Parthenium is useful for compost making and this is the best way of 

managing this weed (Ghosh, 2009). Use of this young plant as green manure is also very useful 

to manage this weed as it contains 3.6 % Nitrogen and around 1.0 % Phosphorus and Potash 

(Dolai et al., 2010). Parthenium contains Sesquiterpene lactones (Ambrosin; Hymenin and 

Parthenin) besides Phenols and other Phenolic acids. The Parthenium extracts are also useful as 

bio herbicides, 5% water extract is able to control the grassy weeds. The root powder is used as 

herbicide to control Cyperus rotundus (Ghosh et al., 2007). A good quality fibre is obtained from 

its stem fibre. It is used for paper pulp purpose. Pre flowered Parthenium provide a potential 

source of protein, vitamin A, vitamin E and xanthophylls. It is used in biogas production. The 

extracts of plant parts may be used as an insecticide to control the cotton insect Spodoptera 

litura. 

Procedure of Parthenium compost preparation 

Make a pit of 3 ft depth x 6 ft width x 10 ft length. It should be in open upland place. 

Cover the base surface and side walls of the pit by stone chips or make soil surface 

compact to protect the absorption of compost nutrients by the soil surface by using Lime. 

Use 40 kg soil and 30 kg FYM / Vermicompost in each of 4 layers a pit. 

Collect young Parthenium plants from nearby areas and spread 50 kg on the surface of 

the pit in each layer. 

Use 10 liters of water and spray it on the surface of the layer. 

Sprinkle 500 g Urea or 3 kg Rock phosphate over this for each layer. 

Add Trichoderma viridi @ 50 g layer -1 

Repeat this type of biomass compact layer till 4 layers. 

Cover the pit with soil, dung and husk making a 1 – 1.5 ft dome shape. 

After 4-5 months the well decomposed compost is ready. 

Sieve final compost with 2 cm x 2 cm mesh for packaging in bags. 

Apply 3-5 t ha -1 this eco-friendly balanced Parthenium compost. 

Similar way preparing the field side compost by using the weed plants in the crop, 

vegetables or orchards and also by using aquatic weeds like Eichhornia crassipes which 

is abundantly available in India could be done. These composts have no harmful effects 



74

and are more nutrient rich & less costly than the traditional FYM or even the 

Vermicompost. 

Name of the compost Nitrogen % Phosphorus % Potash % 

Vermicompost 1.61 0.68 1.31 

FYM 0.45 0.30 0.54 

Parthenium Compost (DWSR) 1.05 0.84 1.11 

Parthenium Compost (BCKV) 1.21 0.89 1.34 

(Ghosh, 2010 and DWSR, 2010) 

Awareness Programmes 

Creating awareness among the peoples including the farmers is the another alternative for 

mass eradication of these invasive weeds. In India during the last few years many awareness 

programmes have been conducted by the Ministry of Agriculture, Government of India, the 

Indian Council of Agricultural Research (ICAR), the Directorate of Weed Science Research 

(DWSR), the Directorate of Agriculture in different States, etc. In West Bengal more than 100 

such programmes have been conducted per annum by Bidhan Chandra Krishi Viswavidyalaya 

(BCKV) during the last five years through the Directorate of Extension Education, Krishi 

Vigyan Kendra and adhoc projects sponsored by Corporates or ICAR. The Weed Science, 

Department of Agronomy alone has been conducting around 25 such awareness programmes per 

anuum at various districts of West Bengal since 2006-07 (Ghosh 2005- 10) organized by the 

author. The benefits of these awareness programmes are reported to be satisfactory. 

Conclusion 

In conclusion invasion of plants is a natural phenomenon. Surveys and surveillance are 

essential to find out about the spreading of these species. Research is to be done to find out how 

to limit these weeds through their possible uses. Awareness is needed to make known the 

possible management actions through uses of these species. Lastly, all sectors of the Society – 

the scientists and officers of institutions, government & NGOs, farmers, students and even the 

general public should be involved in managing these invasive plants. 

References 

Directorate of Weed Science Research (DWSR), ICAR (2010) Compost making from Parthenium – Technical 

Extension Bulletin; 2010. 

Directorate of Weed Science Research (DWSR), ICAR (2010) Biological Control of Parthenium – An Eco friendly 

Approach; Technical Extension Bulletin; 2010 

Dolai AK, Bera S, Jana PK & Ghosh RK (2010) Studies on Prospect of Parthenium as Green Manure and Mulch in 

different Cropping Sequence in Inceptisol of West Bengal. Paper presented in ―International Conference on 

Mother Earth- Save it for Future Generations‖; February 13-15, 2010. Organized by Department of 

Environmental Science, The University of Burdwan, West Bengal, India. Gr. VI Abstract No. 6.15 Pp 131 

Ghosh RK (2005) Invasive weed Parthenium menace and its management at Inceptisol: Paper presented in 2 

75 

nd 

International Conference at Bangalore during December 5-7, 2005. 

Ghosh RK (2005-10) Awareness Programmes on System of Intensification; Awareness Programme on National 

Parthenium Week. Awareness Programme on State Parthenium Management Week, etc. 

Ghosh RK, Mondal SS & Maiti S (2007) Modern Weed Science Manual; Published from Department of Agronomy, 

BCKV. 



Ghosh RK, Dolai AK & Pal D (2008) Weed utilization as medicine; Paper presented in the National Symposium on 

Medicinal Plants; FTC, BCKV; March 2008 

Ghosh S (2008) Integrated Weed Management of Rapeseed – Soybean crop sequence; Ph.D. Thesis , Department of 

Agronomy, BCKV (Unpublished) 

Ghosh RK (2009) Invited Paper on Weed utilization- Workshop at DWSR, ICAR, Jabalpur October 20-21, 2009. 

Ghosh RK (2009) Parthenium Compost – an Ecofriendly Balanced Biofertilizer : Leaflet published from BCKV in 

both Bengali and English version. 

Ghosh RK (2009) Management of Invasive weed Parthenium through Integrated approach: Leaflet published from 

BCKV in both Bengali and English version. 

Ghosh RK, Bhattacharyya A & Varshney JG (2009) Ecorestoration of Soil and Water, Production of oils and 

Employment generation by utilizing weed plants. Presentation of Lead Paper in ―National Consultation on 

Weed Utilization‖, 20-21 October 2009 organized by Directorate of Weed Science Research, ICAR, 

Jabalpur, M.P. Abstracts Pp 34-35. 

Ghosh RK (2010) System of Intensification- The Best Alternate Technology for Modern Agriculture : Leaflet 

published from BCKV in both Bengali and English version. 

Ghosh RK (2010) Dynamics of Anthrophytes in West Bengal: Management of Invasive weed Parthenium through 

Integrated approach: Leaflet published from BCKV in English version. 

Ghosh RK (2010) Published Book Plant Protection Manual -Weed management Chapter ; Directorate of 

Agriculture, Government of West Bengal 

Ghosh RK, Sharma L, Barman S & Dolai AK (2009) System of Intensification: The Alternate Approach for 

Increasing Production of Field Crops. Journal of Crop and Weed 5(2), 63-67. 

Joseph PV (2005) Published paper by the Scientists at the Cochin University of Science and Technology; Current 

Science, August 25, 2005 

National research Centre for Weed Science (NRCWS), ICAR (2008) Making Pathenium Compost– Technical 

Extension Bulletin 35; 2008 



76

Niche modeling in invasive plants: new insights to predict their potential distribution in the 

invaded areas 

Ro Bustamante 1,2 , PC Guerrero 1,2 , FT Peða-Gñmez 1,2 

1 Departamento de Ciencias Ecológicas, Facultad de Ciencias, Universidad de Chile. 

2 Institute of Ecology and Biodiversity. 

E-mail: ramironte@gmail.com 

Introduction 

The explosive spread of some invasive plant species worldwide is an issue of 

major concern for biodiversity conservation. The prediction of future 

distribution of invasive plants as well as the causes of spread are essential for 

the prioritization, the early detection and the control of this global threat. 

Niche-based models have proven to be useful to address these questions. In this 

chapter, we provide the conceptual basis of the niche modeling approach; we 

briefly discuss the methods of common use and the strategies of frequent use in 

invasion ecology as well as some limitations. We present an example of the 

niche modeling of an herbaceous plant originating from California and a 

successful invader in Mediterranean ecosystems. Finally, we present some 

caveats about the potentialities and limitations of this approach. 

Biological invasions represent a growing threat to the conservation of biodiversity (Pimentel 

2002). A general feature of species invasion is that once exotic species establish into a new 

environment, it is very difficult to eradicate and/or predict its spread. These difficulties are 

critical in the case of some invaders whose spread encompasses in some cases entire continents 

(Elton, 1958; Garcìa-Ramos & Rodrìguez 2002; Brooenniman et al., 2007). The understanding 

of the causes of these geographical expansions as well as their ecological consequences is a 

central issue in ecology and conservation biology. Niche-based models have proven to be useful 

in predicting future distribution of invasive plants which is essential for priorization, early 

detection and control. In this essay, we examine the conceptual bases of niche-based modeling; 

we provide one example of niche modeling using Eschscholzia californica, a perennial herb 

originating from California (California poppy) and a successful invader across Mediterranean 

ecosystems. We then discuss the potentialities as well as the limitations of this approach to 

predict geographic distributions of invasive species. 

The niche and the biotope 

The niche is a central concept in ecology and evolution (Wiens et al., 2005; Pearman et al., 

2008). The definition, formerly proposed by Hutchinson (1957), can be summarized as an ―ndimensional 

hypervolume, every point in which correspond to a state of the environment which 

would permit a species to exist indefinitely‖. Two components are recognized within this 

concept: the fundamental niche, i.e. the hyper-volume of one species in absence of biotic/abiotic 

constraints and the realized niche i.e. the resulting hyper-volume including ecological 

77 



interactions. The fundamental niche is greater than the realized niche, given that negative 

interactions are predominantly important in natural communities (Hutchinson, 1957). 

Although the multivariate niche proposed by Hutchinson is an abstract concept, ecologists 

early recognized a reciprocal correspondence between the niche and the physical space in which 

species live (Grinnell, 1917; Hutchinson, 1978). More recently, this correspondence was 

formalized asserting a reciprocal duality between the niche and the biotope (Cowell & 

Rangel,2009); the biotope being the geographical space where individuals, populations or 

species occur, defined by the suitable configuration of the environmental variables, relevant for 

their fitness. Basically, the duality refers to a reciprocal correspondence between each point in 

the hyper-volume niche of one species and one or more points in the geographical space (the 

biotope), thus giving rise to the spatial distribution of the species. Thus, according to this duality, 

niche theory is contributing to identify to what extent changes of the biotope (habitat 

fragmentation, deforestation and climatic change) is contributing to shape the geographical 

distribution of a species. 

The niche-based modeling 

The reciprocal duality between the niche and the biotope constitutes the conceptual basis of 

the niche-modeling approach. The main goal of this approach is to search for predictive 

quantitative models based on the correlation of environmental data with species occurrences 

(Thuiller et al., 2007). In this approach, the biotope is represented as the area and the empirical 

points of occurrences characterized by a vector of n niche variables. Currently, climatic variables 

are available for these purposes at global scale (Hijman et al. 2005), thus, they are useful to 

model the ―climatic niche‖ and the biotope worldwide. The duality allows the projection of each 

point within the climatic niche onto the geographic space. As a single point within the niche 

corresponds commonly to many points in the biotope, it is possible to project the potential 

geographic distribution of a species beyond the observed occurrences, assuming no biotic or 

dispersal constraints. 

The niche modeling assumes that the distribution of species at geographic scales depends 

mostly on climatic factors (Pearman et al., 2008). Indeed, the climatic niche is constructed with 

the occurrences of species (the raw data from which we put the models to work), thus 

representing the portion of space that includes the climatic conditions sustaining survival and 

reproduction minus the sites where occurrences are prevented due to negative interactions and/or 

dispersal limitation. The more the biotic and dispersal limitations become less important, the 

more the climatic niche will resemble the fundamental niche. 

Niche modeling and invasive species 

The niche modeling has been a useful tool to predict the spread of invasive species (Bradley 

BA & Mustard, 2006; Beaumont et al., 2009; Broennimann et al., 2007; Broennimann & Guisan, 

 

Duality refers to phenomena having a twofold nature and characterized by states that are mutually 

exclusive. The duality is also a principle that allows that one concept defined in one dominium be transported 

to other dominium; this operation may be reciprocal (if dual of A is B, then the dual of B is A). 

78 



2008; Fitzpatrick et al., 2007; Kadoya et al., 2009). Since species invasions in global and 

regional scales are thought to be regulated by climatic conditions (Guisan & Zimmermann 2000; 

Pearson & Dawson 2003; Thuiller et al., 2005), these models are mostly applied in the 

assessment of the invasion risks across the new invaded areas (Bradley & Mustard 2006), and 

also attempt to anticipate species invasions in a context of global change (Hughes 2003; Peterson 

et al., 2002; Pearson & Dawson, 2003; Root et al., 2003; Thomas et al., 2004; Hijmans & 

Graham 2006; Bradley et al. 2009). Different strategies have been proposed to predict the 

potential distribution of invasive species: 

(i) to predict the invasion by means of the projection of the original niche to potentially invaded 

areas. This strategy assumes niche conservatism i.e. the tendency of the invasive species to 

maintain ancestral ecological requirements (Wiens & Graham 2005). This assumption may not 

necessarily hold true for some species for which niche evolution is well documented 

(Broenniman et al., 2007). 

(ii) to predict the invasion by projecting a ―regional niche‖ to potentially invaded sites 

constructed with the pooled occurrences collected across native and invaded ranges 

(Broennimann & Guisan 2008; Beaumont et al., 2009). This strategy is more accurate than 

strategy (i) because it encompasses more information for the prediction but it shares the 

assumption of the niche conservatism. 

(iii) to compare the projected distributions in the invaded area from the ―native niche‖ with the 

projected distribution in the same area from the ―introduced niche‖. This strategy assumes the 

possibility of niche evolution; if the niche is conserved, then no discrepancies exist between 

comparisons; when distributions do not coincide between each other, then evolutionary 

phenomenon is a possible option (Fitzpatrick et al., 2007; 2008). More recently, these reciprocal 

comparisons have been improved assessing quantitative evaluations of niche similarity (when the 

niches of two species are more similar than expected by chance) and niche equivalency (when 

the niches of two species are identical) (Warren et al., 2008). 

Niche modeling of Eschscholzia californica: Chile versus California 

Eschscholzia californica Cham. (Papaveraceae), is an endemic plant, originating from western 

North California and is regarded as a successful invader in other Mediterranean zones of the 

world such as Central Chile, Southafrica and medierranean basin, Europe (Stebbins, 1965; Leger 

& Rice, 2007). It is a perennial, self-incompatible and insect-pollinated plant (Cook, 1962). Seed 

dispersal is explosive, spreading seeds up to 2 m away from the mother plant. This plant is a 

successful colonizer across a wide range of environmental conditions either in native and 

introduced ranges, often occupying open, naturally disturbed environments and the edges of the 

roads (Cook, 1962; Leger & Rice, 2003). In Chile, the introduction of E. californica probably 

occurred from multiple introductions during the mid-1800s to early 1900s. It was introduced into 

botanic gardens in coastal and inland cities (Frias et al., 1975; Arroyo et al., 2000), and it is also 

likely that it was accidentally introduced through the commercial importation of alfalfa seed 

(Hillman & Henry, 1928). 

In Central Chile, E. californica is a very common plant. Although it is known to occur 

punctually at the northernmost of Chile at 18þS (3000 m.a.s.l.), the main distribution range is 

between 18þ to 38þ latitude S and from 0 to 2200 m.a.s.l. in Chile (Arroyo et al., 2000). A 



79

emarkable phenotypic variation across a variety of environments have been document, product 

of local adaptation (Leger & Rice, 2007). 

Of the five Mediterranean-type climate regions of the world, central Chile and California have 

the highest similarity in climates and geomorphology (Mooney et al., 1977; di Castri, 1991; Sax, 

2002; Jimenez et al., 2008). Both regions also show a parallel latitudinal-climatic gradient, with 

higher precipitations and lower temperatures at higher latitudes, which shape the patterns of 

distribution of natural vegetation vegetation (Mooney et al., 1977; Sax, 2002; Jimenez et al, 

2008). Furthermore, coastal and interior mountain ranges and central valleys are remarkably 

comparable between Chile and California, having equivalent local climatic effects (Mooney et 

al., 1977). Under this climatic similarity, it is expected that Eschscholzia californica would 

established successfully in Central Chile with no further evolutionary change. 

Occurrence data from California were obtained from the ―Consortium of California Herbaria‖ 

and from CALFLORA. Occurrence data from Chile were obtained from the herbarium of the 

University of Concepcion (CONC) and the National Natural History Museum (SGO). We 

gathered additional occurrence data from field excursions conducted across Central Chile 

(Spring to Summer 2009). The occurrences were associated with temperature and precipitation 

variables, obtained from BIOCLIM (Hijmans et al. 2005, Hijmans & Graham 2006). The 

variables selected in this case were: BIO1, BIO5, BIO10, BIO11, BIO12, BIO15, BIO18, 

BIO19 . 

For climatic niche comparison between Chile and California, we conducted a Principal 

Component Analysis (PCA) (Broennimann et al., 2007; Fitzpatrick et al. 2007), using the 

occurrence data and the climatic variables obtained from BIOCLIM. 

Basically, the PCA summarizes the most important climatic variables that better explain the 

occurrences; thus, using the values of occurrences associated to the Principal Components, it is 

possible to compare statistically the climatic niche between regions (Graham et al. 2004; 

Broennimann et al., 2007; Fitzpatrick et al. 2007). 

For the niche projection into the biotope we used MAXENT (Philips et al 2006), a machinelearning 

algorithm that models the species potential distribution using the occurrences and the 

environmental predictors obtained from BIOCLIM. In different tests, MAXENT has revealed 

better results than comparative methods and is relatively insensitive to a low number of 

occurrences which may be the case in some studies (Elith et al. 2006; Hernandez et al. 2006; 

Pearson et al., 2007). Basically, MAXENT finds a distribution of probability occurrences that 

satisfies the constraints imposed by environmental variables and occurrence data (Phillips & 

Dúdik 2008). In order to do that, the software selects the distribution that maximizes the entropy, 

in this case, the uniform distribution. The spatial resolution of maps displaying the potential 

distribution is 1 x 1 km 2 . MAXENT also allows to test the models by the calculation of the area 

under the receiver operating characteristic curve (AUC) which represents the relationship 

 

BIO1: mean annual T, BIO5: maximum T, warmest month; BIO10: maximum T, warmest quarter, BIO11: 

Mean T, coldest quarter, BIO12: Annual PP, BIO15: PP seasonality, BIO18: PP warmest quarter, BIO19: PP 

coldest quarter. (T: temeperature; PP: precipitation) 

80 



etween the ability of the model to predict occurrences given that they effectively occur versus 

the ability to predict occurrences given that they do not occur (Phillips et al., 2006). For good 

models, the slope of this relationship must be higher than 0.8. 

The current geographic distribution of Eschscholzia californica was compared in Chile with 

the projected distribution. Specifically, we compared the distribution model projected in Chile 

from the climatic niche described for California (Californian niche) against the distribution 

model projected in Chile from the climatic niche described for Chile (Chilean niche). In order to 

do that we used the statistic proposed by Warren et al. (2008): 

1 

2 

I( px 

, p y ) 1 

H( 

px 

, p y ) , H ( px 

, p y ) ( px, 

i p y, 

i ) . In this case, px,i (or py,i) 

2 

i 

denotes the probability distribution assigned to species i onto the coordinate (x,y) from the 

distribution model projected from the Californian and from Chilean niche, respectively. This 

statistic ranges from 0 (no similarity) to 1 (total similarity). The differences between distribution 

models were statistically tested by randomnization procedures using the software ENM Tools 

(Warren et al. 2010). If the niche of Eschscholzia californica is conserved, then both distribution 

models should be significantly similar; if niche shift has occurred, then the distribution models 

should be tend to be dissimilar each other. 

Niche comparison 

The eight selected climatic variables were reduced into two Principal Components Principals: 

PC1, explained approximately 75% total variance of data, thus representing mainly precipitation; 

PC2, represented aprox 15% total variance and represented temperatures. A graphic 

representation of the niche space indicates that the occurrences of E. californica in California 

encompassed a larger portion of the niche space while in Chile, they are restricted to the more 

mesic and coldest portion of the niche space; globally, the Chilean niche is nested within the 

Californian niche (Figure 1), particularly concentrated in the more mesic and coldest part of the 

environmental gradient. 

This result is presumably the consequence of a non-random arrival of E. californica 

propagules that shared similar climatic requirements. In fact, the geographic projection of the 

Californian occurrences that were inside the Chilean niche, indicated that they are located 

exclusively at the coastal range of California (Peða et al. unpublished data) which suggests that 

the introductions were multiples and occurred exclusively from coastal populations. Given that 

the Chilean niche occurs almost completely inside the Californian niche, this nestedness is also 

an evidence of niche conservatism i.e. the set of invaders that arrived to Chile maintained their 

original requirements without further shift in the invaded range. Genetic analysis and interregional 

comparisons will be appropriate to shed further light on these questions. 



81

Figure 1 - Climatic niche space of Eschscholzia californica for California (Californian niche, 

open dots) and Chile (Chilean niche, black dots) obtained from the Principal Component 

Analysis (PCA). The first two axes of the PCA represent variation of precipitations (Principal 

Component 1) and temperature (Principal Component 2), respectively. The two ellipsoids 

include the 95% confidence intervals for California and Chile. 

Projections of E. californica in Chile 

The geographic distribution of E. californica in Chile projected from the Chilean niche and 

the Californian niche are shown in (Figure 2A and 2B). The Californian niche projected a larger 

distribution area (234798 km 2 ) than the Chilean niche (area: 79809 km 2 ) (Figure 2a and 2B). In 

fact, the Californian niche projected a potential distribution to coastal deserts in Chile and to the 

Patagonian Argentina, but with fairly low occurrence probabilities (P(O) < 0.3) (Figure 2B). 

However, both projections concentrate the highest occurrence probabilities (P(O) ≥ 0.50) at the 

coastal range of central Chile (aprox. 31þ to 36þ latitude S; Figure 2A and 2B). Statistical 

comparison indicated that the estimated similarity index between the two projected distribution 

(I = 0.559) is higher than the critical value (Icrit = 0.558), which indicates that the two projected 

geographic projection are significantly similar each other (Figure 3). 



82

Figure 2A - Geographic distribution of Eschscholzia californica in Chile projected from the 

Chilean niche. Grey tonalities represent different occurrence probabilities. Black dots 

represent the occurrence data for the construction of the model. 



83

Figure 2B - Geographic distribution of Eschscholzia californica in Chile projected from the 

Californian niche. Grey tonalities represent different occurrence probabilities. Black dots 

represent the occurrence data for the construction of the model. 



84

35 

30 

25 

20 

15 

FREQUENCY (N) 

10 

5 

Figure 3 - Similarity index (I) to compare the geographic distribution projected from the 

Californian niche and the geographic distribution projected from the Chilean niche. This 

histogram was obtained comparing the similarity between 400 pairs of pseudo-replicated 

distributions obtained from re-sampling methods (Warren et al. 2008). The black arrow 

represents the estimated similarity index (I = 0.5559) between the Chilean and the Californian 

distribution. Broken line shows the critical value (I = 0.5558) that integrates the 95% of the 

total probability distribution. 

It is interesting to note that the geographic distribution of Eschscholzia californica projected 

from the Californian niche, extends to the northern desert of Chile and to the Patagonia region of 

Argentina. The projection to the northern Chile may be explained because in California this 

occupies desert ecosystems (Clark, 1978). We have preliminary evidence which indicates that 

this species really occurs at San Carlos de Bariloche (Argentinian Patagonia) (Bustamante pers. 

obs.) a fact that supports the projection of the Californian niche to these regions. These results 

may have profound implications for the potential spread of E. californica as the Andean Range 

should act as a biogeographic corridor rather than a barrier at intermediate altitudes, thus 

allowing the spread of this species beyond Andean ranges. 

Caveats 

BACKGROUND SIMILARITY TEST 

0 

0,5493 0,5507 0,5521 0,5536 0,5550 0,5565 

0,5500 0,5514 0,5529 0,5543 0,5558 0,5572 

SIMILARITY INDEX (I) 

The use of ecological niche models will increase in the future because they are based on a 

well accepted theoretical background (niche theory). They are also based on occurrence data 

which are relatively easy to gather relative to other measurements of plant performance such as 

85 



eproductive outputs, survival or density. An additional advantage is that the global climatic 

information and appropriate software to conduct niche modeling are available (for free) in the 

web (www.worldclim.org). 

However, there are some conceptual/methodological limitations that should be considered 

during the use this correlative approach. Firstly, niche may evolve during the invasive process, 

thus projected distribution may be underestimated drastically if we assume niche conservatism. 

Secondly, biotic factors may be as important as climatic factors to drive the geographic spread in 

invasive plant; this information is often unavailable to be included in these models and therefore 

a strong effort should be made to fill this missing issue. Thirdly, human activities impose notable 

changes in the landscape, not always considered in niche modeling of invasive species, even 

though, humans are a major vector in species spread. Thus, it is mandatory to get detailed spatial 

data describing the human footprints across landscapes (disturbances, roads, cities, population 

density). Fourthly, niche-based models are sensitive to the number of climatic variable selected: 

too many variables can over-fit the models and therefore fail to predict the full invasive potential 

of a species, but too few can leave out relevant climatic variables where a species could have 

shifted or expanded. 


This study was supported by project FONDECYT 1100076 to RO Bustamante and project 

ICM P05 – 002; Pablo Guerrero is a fellow of CONICYT (D-21070301, AT-24090076, 

75100024) and Fulbright (15103515). WE acknowledge the assistance and help of Lua Alves 

and Juan Pablo Martinez for the data analysis and help during the execution of this study. 

References 

Arroyo MTK, Marticorena C, Matthei O & Cavieres L (2000) Plant invasions in Chile: present patterns and future 

predictions. In Invasive Species in a Changing World (eds Mooney HA & Hobbs RJ), pp 385–421. Island 

Press, Washington DC. 

Beaumont LJ, Gallagher RV, Thuiller W, Downey PO, Leishman MR & Hughes L (2009) Different climatic 

envelopes among invasive populations may lead to underestimations of current and future biological 

invasions. Diversity and Distributions 15, 409-420. 

Bradley BA & Mustard JF (2006) Characterizing the landscape dynamics of an invasive plant and risk of invasion 

using remote sensing. Ecological Applications 16, 1132-1147. 

Broennimann O & Guisan A (2008) Predicting current and future biological invasions: both native and invaded 

ranges matter. Biology Letters 4, 585-589. 

Broennimann O, Treier UA, Müller–Scharer H, Thuiller W, Peterson AT & Guisan A (2007) Evidence of climatic 

niche shift during biological invasion. Ecology Letters 10, 701 – 709. 

Cook SA (1962) Genetic system variation and adaptation in Eschscholzia californica. Evolution 16, 278–299. 

Clark C (1978) Systematic Studies of Eschscholzia (Papaveraceae) I. The origin and Affinities of E. Mexicana. 

Systematic Botany 3, 374-385. 

Colwell RK & Rangel FR (2009) Hutchinson‘s duality: the once and future of niche. Proceeding of the National 

Academy of Science 106, 19651 – 19658. 

Di Castri F (1991) An ecological overview of the five regions of the world with a mediterranean climate. In 

Biogeography of Mediterranean invasions (eds Groves RH & Di Castri F), pp 3 – 16. Cambridge : 

Cambridge University Press. 

Elith J, Graham CH, Anderson RP, Dudı´k M, Ferrier S, Guisan A, Hijmans RJ, Huettmann F, Leathwick JR, 

Lehmann ALJ, Lohmann LG, Loiselle BA, Manion G, Moritz C, Nakamura M, Nakazawa Y, Overton JMcC, 

Peterson AT, Phillips SJ, Richardson KS, Scachetti - Pereira R, Schapire RE, Soberñn, J, Williams S, Wisz 

MS & Zimmermann NE (2006) Novel methods to improve prediction of species distributions from 

occurrence data. Ecography 29, 129 - 151. 



86

Elton C (1958) The ecology of invasions by animals and plants. Metheun and Co, London. 

Jiménez A, Pauchard A, Cavieres LA, Marticorena A & Bustamante RO (2008) Do climatically similar regions 

contain similar alien floras? A comparison between the mediterranean areas of central Chile and California. 

Journal of Biogeography 35, 614 – 624. 

Fitzpatrick MC, Weltzin JF, Sanders NJ & Dunn RR (2007) The biogeography of prediction error: why does the 

introduced range of the fire ant over-predict its native range? Global Ecology and Biogeography 16, 24-33. 

Fitzpatrick MC, Weltzin JF, Sanders NJ & Dunn RR (2008) Data sets matter but so do evolution and ecology. 

Global Ecology and Biogeography 17, 562-565. 

Frias DL, Godoy R, Iturra P, Koref-Santibanez S, Navarro J, Pacheco N & Stebbins GL (1975) Polymorphism and 

geographic variation of flower colour in Chilean populations of Eschscholzia californica. Plant Systematics 

and Evolution 123, 185–198. 

Garcìa-Ramos G & Rodriguez D (2002) Evolutionary speed of species invasion. Evolution 56, 661 – 668. 

Graham CH, Ferrier S, Huettman F, Moritz, C & Peterson AT (2004) New developments in museum-based 

informatics and applications in biodiversity analysis. Trends Ecology and Evolution 19, 497–503. 

Grinnell J (1917) The niche relationships of the California thrasher. The Auk 34, 427–433. 

Guisan A & Zimmermann NE (2000) Predictive habitat distribution models in ecology. Ecological Modeling 135, 

147–186 

Hernandez PA, Graham CH, Master LL & Albert DL (2006) The effect of sample size and species characteristics on 

performance of different species distribution modeling methods. Ecography 29, 773–785 

Hijmans RJ, Cameron SE, Parra JL, Jones PG & Jarvis A (2005)a Very high resolution interpolated climate surfaces 

for global land areas, International Journal of Climatology 25, 1965–1978 

Hijmans RJ & Graham CH (2006) The ability of climate envelope models to predict the effect of climate change on 

species distributions. Global Change Biology 12, 2272–2281 

Hillman FH & Henry HH (1928) The Incidental Seeds Found in Commercial Seed of Alfalfa and Red Clover. 

Proceedings of the International Seed Testing. pp. Vol 6, 1–20. Association Copenhague, Copenhague. 

Hughes L (2003) Climate change and Australia: Trends projections and impacts. Austral Ecology 28, 423-443. 

Hutchinson GE (1957) Concluding remarks Cold Spring Harbor Symposia. Quantitative Biology 22, 415–427 

Hutchinson GE (1978) An Introduction to Population Biology. Yale University Press, New Haven, Connecticut 

Kadoya T, Ishii HS, Kikuchi R, Suda S & Washitani I (2009) Using monitoring data gathered by volunteers to 

predict the potential distribution of the invasive alien bumblebee Bombus terrestris. Biological Conservation 

142, 1011-1017 

Leger EA & Rice KJ (2007) Invasive California poppies (Eschscholzia californica Cham) grow larger than native 

individuals under reduced competition. Ecology Letters 6, 257-264 

Mooney HA (ed) (1977) Convergent Evolution in Chile and California: Mediterranean Climate Ecosystems. 

Dowden Hutchinson & Ross, Stroudsburg, Pennsylvania. 

Pearman PB, Guisan A, Broennimann O & Randìn CF (2008) Niche dynamics in space and time. Trends in 

Ecology and Evolution 23, 149 – 158. 

Pearson RG & Dawson TP (2003) Predicting the impacts of climate change on the distribution of species: are 

bioclimate envelope models useful? Global Ecology & Biogeography 12, 361-37. 

Pearson RGC, Raxworthy J, Nakamura M & Peterson AT (2007) Predicting species distributions from small 

numbers of occurrence records: a test case using cryptic geckos in Madagascar. Journal of Biogeography 34, 

102–117. 

Peterson AT, Stockwell DRB & Kluza DA (2002) Distributional prediction based on ecological niche modeling of 

primary occurrence data In: Predicting Species Occurrences: Issues of Scale and Accuracy (eds Scott JM, 

Heglund PJ Morrison ML et al), pp. 617–623. Island Press Washington DC. 

Pimentel D (ed) (2002) Biological Invasions Economic and environmental costs of alien plants animals and microbe 

species. CRC Press, Florida 

Phillips SJ, Anderson RP & Schapire RE (2006) Maximum entropy modeling of species geographic distributions. 

Ecological Modeling 190, 231–259. 

Phillips S & M Dudìk (2008) Modeling of species distributions with Maxent: new extensions and a comprehensive 

evaluation. Ecography 31, 161–175. 

Root TL, Price JT, Hall KR, Schneider SH, Rosenzweig C & Pounds JA (2003) Fingerprints of global warming on 

wild animals and plants. Nature 421, 57 – 60. 

Sax DF (2002) Native and naturalized plant diversity are positively correlated in scrub communities of California 

and Chile. Diversity & Distributions 8, 193 – 210. 



87

Stebbins GL (1965) Colonizing species of the native California flora In: The Genetics of Colonizing Species (eds 

Baker HG & Stebbins GL). Academic Press, New York. 

Thuiller W, Richardson DM, Pysek P, Midgley GF, Hughes GO & Rouget M (2005) Niche-based modelling as a 

tool for predicting the risk of alien plant invasions at a global scale. Global Change Biology 11, 2234–2250. 

Thuiller W, Richardson DM & Midgley GF (2007) Will climate change promote alien plant invasions? In 

Ecological studies (eds Nentwig W), pp. 197–211. Springer Berlin, Berlin. 

Thomas CD, Cameron A, Green RE, Bakkenes M, Beaumont LJ, Collingham YC, Erasmus BFN, Ferreira de 

Siqueira M, Grainger A, Hannah L, Hughes L, Huntley B, van Jaarsveld AS, Midgely GE, Miles L, Ortega- 

Huerta MA, Peterson AT, Phillips OL & Williams SE (2004) Extinction risk from climate change. Nature 

427, 145–148. 

Warren DL, Glor RE & Turelli M (2008) Environmental niche equivalency versus conservatism: quantitative 

approaches to niche evolution. Evolution 62, 2868-2883. 

Warren DL, Glor RE & Turelli M (2010) ENMTools: a toolbox for comparative studies of environmental niche 

models. Ecography 33, 607- 611. 

Wiens JJ & Graham CH (2005) Niche conservatism: integrating evolution ecology and conservation biology. 

Annual Review Ecology Evolution and Systematics 36, 519 – 536. 



88

Bern Convention on invasive alien plants, the Code of conduct on horticulture and invasive 

alien plants 

Eladio Fernandez-Galiano 

The Council of Europe, 67075 Strasbourg Cedex, France, E-mail: eladio.fernandezgaliano@coe.int 

The Council of Europe was founded in 1949 and seeks to develop throughout Europe common 

and democratic principles based on the European Convention on Human Rights and other 

reference texts on the protection of individuals. The Council of Europe is composed of 47 

member countries and one applicant country. 

The Convention on the Conservation of European Wildlife and Natural Habitats was adopted in 

Bern in 1979. It counts at present 44 Contracting Parties, one of which is the European 

Commission. The Convention has a three-fold objective: 

- To conserve wild flora and fauna and their natural habitats 

- To promote co-operation between states 

- To give particular emphasis to endangered and vulnerable species and endangered natural 

habitats. 

The Bern Convention gathers Ministries of Environment and is managed by a Conference of the 

Parties called ―Standing Committee‖ which has met 20 times since the entry into force of the 

Convention in 1982. 

Activities on Invasive Alien Species (IAS) started in 1984 with the launch of a general 

recommendation for member countries. Specific recommendations were then adopted on the 

control of Caulerpa taxifolia, on the control of the Ruddy Duck Oxyura jamaicensis, on the 

introduction of the American cottontail rabbit (Sylvilagus sp.) into Europe, on the control of the 

Grey squirrel (Sciurus carolinensis) and other alien squirrels into Europe, on the eradication of 

vertebrates, etc. In 2002, the European Strategy on Invasive Alien Species was adopted aiming to 

provide more guidance to countries to draw up and implement a national strategy on IAS. In 

November 2008, the ―Code of conduct for Horticulture and Invasive Alien Plants‖, project 

developed in partnership with EPPO, was launched. 



89

EPPO activities on Invasive Alien Plants, 

Sarah Brunel 

The European and Mediterranean Plant Protection Organization, 21 Bld Richard Lenoir, 75011 

Paris, France. E-mail: Brunel@eppo.fr 

The European and Mediterranean Plant Organization (EPPO) and the Council of Europe have 

conjointly drafted a Code of conduct on horticulture and invasive alien plants for European and 

Mediterranean countries, which was published in 2009. In Europe, it is estimated that 80% of the 

invasive alien plants are voluntarily introduced for ornamental purposes, and international trade 

is increasing yearly. This major pathway must be addressed urgently to prevent entry and spread 

of invasive alien plants, as at present, few legislation and management programmes are in place. 

Voluntary measures to tackle the problem and raise awareness among the horticultural sector and 

the public are therefore considered a priority. 

This Code of conduct provides essential information for Governments and the horticultural and 

landscape sectors on regulation concerning invasive alien plants, plant waste disposal, labelling 

of plants, proposing alternative plants, publicity, etc. 

This new and promising initiative now requires promotion and implementation within countries. 



90

Role of the European Food Safety Authority in risk assessment of invasive species 

potentially harmful to plants 

Sara Tramontini 1 , V. Kertesz 1 , E. Ceglarska 1 , M. Navajas 2 , G. Gilioli 2 

1 

European Food Safety Authority, Risk Assessment Directorate, I-43100 Parma, Largo Palli 

Natale 5A, Italy 

2 

European Food Safety Authority, Scientific Panel on Plant Health. 

E-mail: sara.tramontini@efsa.europa.eu 

The European Food Safety Authority (EFSA) provides independent scientific advice and 

transparent communication on risks relating to the safety and security of the food chain in the 

European Community. The EFSA Scientific Panel on Plant Health addresses the increasing 

demand of EU risk managers for scientific advice on risks posed by organisms harmful to plants 

and plant products. Advice is published as scientific opinions which provide a basis for 

consideration of phytosanitary measures to protect against the introduction and spread of harmful 

or invasive species in the European Community, under Council Directive 2000/29/EC. Since its 

inception in 2006, the Panel has delivered forty-five scientific opinions on the risks posed by 

species of invasive plants, invertebrate pests and pathogens, and pathways for pest movement. In 

addition, two guidance documents have been published: the first one on the evaluation of pest 

risk assessment and the second on the harmonized process for pest risk assessment and the 

identification and evaluation of pest risk management options. A new mandate for the 

preparation of a third guidance document on the environmental risk assessment (ERA) of plant 

pests (invertebrates, diseases and plants) has recently started. 

The approaches and methodologies currently under discussion in the EFSA ERA Working 

Group for the evaluation of the potential impact of invasive species to the EU environment will 

be presented. An important development foreseen will be the opportunity for collaboration 

between the Working Group and the scientific world engaged in the preparation of 

environmental risk assessment related to the introduction of exotic plants in the EU 

Mediterranean area. 



91

Exploring options for an early warning and information system for invasive alien species in 

Europe 

R Scalera 1 and P Genovesi 1 

1 Invasive Species Specialist Group (IUCN/SSC), Email: scalera.riccardo@gmail.com 

Introduction 

In order to respond adequately to the threat of alien species in Europe, an 

effective early warning and rapid response (EWRR) system should be based on 

a framework of policies and activities. These include measures to detect the 

occurrence of new propagules and invaders, supported by activities to diagnose 

new species correctly and acquire all related information. Such information 

represents a necessary basis for science-based risk assessments that evaluate 

the severity of the threat and consequently identify the best options for 

managing the species. 

Each element of the framework should be under the responsibility of one or 

more competent authorities acting at the European, national or local level. The 

procedure and protocols for an optimal circulation of information can vary 

according to the species in question, the region targeted and the available 

knowledge and tools (including legal instruments, when available). However, 

the efficiency of the system is guaranteed by an optimal and rationalised 

circulation of information among all involved actors through an effective 

European information system. For this reason, a key element for adequate 

coordination of all the activities in a regional EWRR is the establishment of a 

dedicated European technical scientific body. Such a body should ensure 

prompt and transparent access to high level scientific knowledge and expertise 

on the different aspects of the EWRR system, with the primary task of 

implementing and maintaining a European information system on alien species. 

Five possible options for establishing a dedicated technical scientific body are 

identified, implying varying levels of commitment by EU institutions and 

Member States (including differing budgetary and personnel needs). A 

dedicated structure could take the form of a scientific panel, an observatory, or 

a centralised agency at the pan-European level. A further alternative is a simple 

network of experts and/or scientific institutions from individual European 

countries. 

A priority at the EU level is the development of an early warning and rapid response (EWRR) 

system aimed at ensuring a transparent, prompt and reliable flow of information needed to 

support Member States (MSs) in identifying and undertaking appropriate responses to new 

biological invasions. In fact, several studies have shown that until a comprehensive EU strategy 

on IAS will be available, the European capacity to respond to such threat will be limited (see 

Genovesi et al., 2010, Shine et al., 2010, Hulme at al., 2009). The urgency to tackle biological 

invasions has been formally recognised by the European Commission (EC) in its recent 

92 



Communication ―Our life insurance, our natural capital: an EU biodiversity strategy to 2020‖ 

(COM(2011) 244 final). According to the target 5 of this Communication ―By 2020, Invasive 

Alien Species and their pathways are identified and prioritised, priority species are controlled or 

eradicated, and pathways are managed to prevent the introduction and establishment of new 

IAS‖. In addition, in its Communication ―Halting the loss of biodiversity by 2010 and beyond: 

sustaining ecosystem services for human well–being‖ (COM(2006) 216 final) the EC stressed 

the need for coordinated action to reduce substantially the impact of IAS on EU biodiversity. 

Similarly, in its Communication ―Towards an EU Strategy on Invasive Species‖ (COM(2008) 

789 final), the EC has committed to develop a policy on the issue, as well as to establish an early 

warning system. These commitments have been endorsed also by the Council of European 

Ministers in the Conclusions adopted at their 2953rd meeting ―Council Conclusions on a midterm 

assessment of implementing the EU Biodiversity Action Plan and Towards an EU Strategy 

on Invasive Alien Species‖ (Luxembourg, 25 June 2009). Indeed, also the G8 Environment, in 

2009, has stressed the urgent need to combat invasive species, calling the world community to 

establish a global early warning system. 

In this context, a European Environment Agency (EEA) report titled ―Towards an early 

warning and information system for invasive alien species (IAS) threatening biodiversity in 

Europe‖ has been recently published by Genovesi et al. (2010). This study, which has been also 

used as a basis for the present work, describes the EWRR as a framework aimed at responding to 

biological invasions through a coordinated system characterised by a specific workflow of key 

activities. Such activities include the detection of the occurrence of new propagules and invaders, 

supported by activities aimed at a sound diagnosis of the new species and at the acquisition of all 

related information. This should be followed by science based risk analysis aimed at the 

evaluation of the severity of the threat and consequently at the at the resolution best suited for 

their management, and at the enforcement of such measures. In practice, the EWRR ―workflow‖ 

includes 6 key steps, which are linked to each other in the following order: 

1) surveillance and monitoring activities, 

2) data processing (including diagnosis of invading species), 

3) assessment of risks (and/or quick screening), 

4) identification of appropriate management response, 

5) reporting to competent authorities, 

6) enforcement of management response and monitoring/assessment of success of measures 

carried out. 

Each component should be under the responsibilities of competent EU, national or local 

authorities, and the efficiency of the system is guaranteed by an optimal and rationalised 

circulation of information and following a clear shared protocol of actions, setting up procedures 

which can vary according to the species and region targeted, and the available knowledge and 

tools (both technical and legal). 

In any case, in order to guarantee a EU-level leading role in establishing and coordinating a 

common information system to support early detection and effective action against newly 

recorded invasive species (before they spread beyond a point at which eradication is no longer 

possible) a EU dedicated structure on invasive alien species should be established. Such 

dedicated structure could have the form of a scientific panel, an observatory, or a centralised 

93 



agency at the European level. In alternative, a simple network of experts and/or scientific 

institutions from single European countries could be established. Whatever the form, it is 

essential that the above mentioned activities representing the ideal workflow for a sound early 

warning and information system are implemented in a coordinated efficient way. 

Indeed, an effective EWRR system acting at the EU level can be established only after the 

implementation of the following preliminary steps: 

1) Establishment of an EU technical structure, dedicated to invasive alien species, capable 

of guaranteeing (among other tasks) the coordination of the foreseen activities. 

2) Development and maintenance of a EU information system on invasive alien species, 

also facilitating the access to high level scientific expertise. 

3) Development of a system capable of ensuring the circulation of information to the 

competent national/local authorities regarding the data collected (e.g. as a results of the 

surveillance and monitoring activities) and analysed (e.g. as a consequence of the quick 

screening/risk analysis), as well as the recommended response actions (e.g. management 

measures). 

4) Establishment of a mechanism to monitor the prompt and correct implementation of the 

measures for contingency planning and rapid response as recommended by the EU 

technical structure to the competent national/local authorities. 

The EU technical structure dedicated to invasive alien species 

With regard to the establishment of a dedicated EU structure on alien species, the EEA report 

(Genovesi et al., 2010) contributed to the identification of five options, which take into account 

different levels of commitment by EU institution and Member States, and which also reflects 

differential budgetary and personnel requirements. Such options are the result of an evaluation of 

costs and benefits made on the basis of similar panels of experts, observatories and agencies 

already established and acting at the pan-European level, and that are characterised by the same 

kind of needs as invasive alien species (e.g. EPPO, NOBANIS, EFSA, Joint Research Centre - 

JRC). 

The essential role of such a technical body would be to provide a European-wide central 

scientific body, with access to high level scientific expertise on the different aspects of a EWRR, 

and with the key task of implementing and maintaining a European information system on alien 

species. It must be stressed that a EU structure on alien species would not only support an 

EWRR system, but would also provide the technical basis for other crucial aspects of a EU 

strategy and policy on biological invasions, such as the development of regional black or white 

lists of regulated pests, the support to decision making on trade regulations, the development and 

update of indicators, etc. 

The details of the different options 0, A, B, C, D and E are discussed below. 

Option 0: Do nothing 

In this case, the development of an early warning system or of a part of its components is left 

to the responsibility of the national and local authorities of the interested countries. Therefore it 

does not require any EC support. This option is the least costly but also the least effective 

because of the total sum of the costs incurred by each single country in order to tackle the 

94 



problem of IAS. To ensure the needed performances the cost to support single early warning 

systems in all MSs is likely to exceed 10 million €/year. This would be much higher than the cost 

of establishing a EU centralised framework able to support MSs (which would significantly 

reduce the costs of national activities by gradually increasing synergies among countries, as 

shown by the other options below). This option might be apparently the least onerous for the EU 

institutions, but would lead to a number of major shortcomings: 

Limited coordination, limited harmonisation and risk of inconsistencies among actions 

undertaken by different countries; 

No significant progress from the present – unsatisfactory – level of action; 

Inadequate action by even a single country would put at risk the entire community, 

including other more active countries; 

The lack of mandatory commitment might prevent the effective establishment of a 

comprehensive network, with the inherent risk of failure of the entire strategy and 

compliance with the provisions suggested by the recent EC communications; 

Lack of adequate exploitation of the successful results achieved through the resources so 

far invested by the EC and/or MSs for developing projects such as DAISIE, NOBANIS, 

PRATIQUE, etc. 

Option B: Non-institutional EU panel of experts (DAISIE-NOBANIS approach) 

This option foresees the establishment of a technical/scientific panel of experts and 

institutions and/or government agencies (such as the DAISIE consortium and the NOBANIS 

network). It is therefore an independent non-institutional initiative, not necessarily supported by 

national authorities. The structure would be very simple and low cost, easy to manage and would 

mostly act by maximising the use of existing technical instruments. The panel would be only an 

advisory body, with no regulatory role, therefore the enforcement of measures is entirely left to 

the voluntary commitment of countries. 

On the basis of the experience by members of the DAISIE consortium, it is estimated that the 

panel should be coordinated by one chair and one program officer working full time, and should 

be composed by a team with expertise on the key aspects of biological invasions, and with ad 

hoc coordinators for each taxonomic group (i.e. 10 experts covering main taxonomic groups, and 

with competence across management techniques). Some additional part-time specialists should 

be employed by the scientific institutions forming the consortium, under the supervision of 

taxonomic coordinators. Periodic meetings (1-2/year) should be foreseen. 

Depending on the availability of funds, basic duties of the panel would be to: 

Maintain and update a freely accessible portal and database; 

Regularly update information for the database; 

Circulate general information on invasive species to all involved/competent actors; 

Provide advice and information to national authorities and management bodies to assist 

in the identification of new species, assessment of risks, identification of possible 

responses; 

Raise awareness and improve national response efficacy by circulating information 

among national authorities and the general public. 

The costs for the creation of the network of experts (employment of part time scientific staff and 

central coordination staff), organisation of meetings and maintenance/updating of the inventory 

is estimated at 500 000 €/year. 



95

Basically, the panel would depend on the commitment of the involved partners, with the concrete 

risk of lack of continuation due to uncertainty in resources allocation. The financial resources 

could be partly covered for a limited number of years with existing EU financial instruments (i.e. 

LIFE+), and/or with contributions from authorities and institutions of single states (e.g. as in 

NOBANIS) and private sponsors. However, this would not guarantee the activities in the 

medium-long term, and the lack of a legal basis and political mandate would reduce the 

efficiency of the internal organisation of work, as well as the impact of the work in terms of early 

warning and rapid response. 

Option C: EU observatory based on clear political mandate (NISC approach) 

This option foresees the establishment of a permanent Observatory on Invasive Species (OIS) 

through a formal policy decision by EC and/or MSs. The decision could be taken within the 

adoption of a EU policy on invasive alien species, and would therefore not necessarily require a 

complex decision process. The main task of this sort of intergovernmental body (like in EPPO), 

would be to coordinate and assist MSs in enforcing policies and measures consistent with EC 

general directions, without a binding role on national actions. However, the limited institutional 

role may facilitate – although not guarantee – improved enforcement of measures by national 

authorities. For this purpose, the OIS should host a EU information system on invasive species to 

support decision making and management. 

The OIS should be led by a steering committee or council to define a program of activities and 

ensure implementation, and should include a core management team of 5-7 full time specialists, 

(with expertise covering the most abundant/problematic taxonomic groups) plus some additional 

staff for IT support and secretariat work (2 full time positions). Work structure could include the 

organisation of technical/scientific panels (i.e. taxonomy, risk assessment) and of ad-hoc 

thematic working groups. 

Funding and structures should be provided in order to guarantee long term activities such as: 

Hosting and maintaining a freely accessible portal and database on IAS and relative 

experts, constantly updated; 

Establishing a voluntary reporting mechanism by MSs - based for example on 

memorandums of understandings signed by OIE and MSs - on new detected incursions, 

enforced response activities, etc.; 

Providing assistance for identifying newly recorded taxa, if required; 

Performing quick screening of risks when appropriate, and developing alarm lists, watch 

lists, etc.; 

Performing formal risk analysis when appropriate (in coordination with relevant 

European bodies such as EFSA or the EEA if needed);Collecting and disseminating 

information on specific management techniques; 

Developing technical recommendations to countries and European institutions; 

Circulating general information on invasive species. 

Considering the limited staff, the OIS could be hosted by an already existing technical or 

scientific institution (such as JRC, EEA or EPPO) to reduce the costs for infrastructure. The 

overall budget should be of about € 2 million (of which € 500 000 for the maintenance of a 

dedicated information system). The budget may be covered through national voluntary 

contributions (as in the EPPO system) with additional financial support from either the EC or the 

hosting country. 



96

The presence of specialised permanent staff would guarantee a major improvement in the 

technical capability to deal with the complex tasks of an EWRR framework. Continued financial 

support would ensure the sustainability of the results and the possibility to make best use of the 

available information systems and tools in the medium term. In addition, a more solid structure 

would enable the OIS to provide more solid technical support to MSs and more efficient 

coordination with existing EU or European institutions (EPPO, EFSA, etc.) 

Option D: EC Agency with legal mandate and financial continued support (ECDC approach) 

This option aims at the establishment of a Community Agency through a founding regulation, 

based on a new or revised EC legislation (e.g. with an approach similar to that used to found the 

European Centre for Disease Control - ECDC). The EU Agency on Invasive Species (EAIS) 

should promote enforcement of legal provisions on the issue, coordinating national actions and 

assisting MSs in the enforcement of policies on the issue, by supporting the detection of new 

incursions of alien species, assessing the inherent risks, identifying appropriate responses. 

The EAIS should be governed by a management board, laying down the general guidelines and 

adopting the work programmes, including available resources and political priorities. The 

executive director would be responsible for all activities of the agency and the proper 

implementation of its work programmes. The Agency should be supported by a scientific 

committee made up of leading experts on the issue, covering the main taxonomic groups of 

interest. In total, the structure should consist of 10-15 scientific experts, and 3-5 IT experts (in 

total about 30-40 people, including administrative staff). 

The EAIS should be an independent scientific body, working in close collaboration with the EC, 

the national authorities and other competent bodies (EPPO, EFSA, European Maritime Safety 

Agency - EMSA, etc). Moreover the agency should work in compliance with other community 

and European alert systems (e.g. animal health, food safety, EPPO, etc) and should ensure open 

consultation with key stakeholders. EAIS should host the European information system on 

invasive species, and therefore should be provided with adequate and secured funds and 

structures to make best use of such an agency, and to enhance linking with other existing 

European and global tools. The role of the EAIS should be partly regulatory, for example 

producing opinions on proper responses to be adopted by MSs. For this reason a standardised 

and transparent mechanism to process the information on the basis of rigorous scientific criteria 

should be ensured. 

The main possible tasks of EAIS would be: 

Hosting and maintaining a freely accessible portal and updated database; 

Collecting information from single experts/institutions/MSs; 

Establishing a reporting mechanism (similar to the EPPO one, but covering also taxa 

other than plants and plant pathogens) on new detected incursions, enforced response 

activities, etc; 

Providing assistance for identifying taxonomy of specimen; 

Maintaining and constantly updating an experts registry; 

Performing quick screening and risk assessments when appropriate; 

Performing independent evaluation of risk analysis carried out by otherauthorities; 

Accessing and disseminating information on management techniques; 

Developing technical recommendations, in the form of formal opinions, to MSs and 

European institutions; 



97

Developing and circulating to MSs and competent authorities alarm lists, watch lists, etc.; 

Coordinating the initiatives regarding the implementation of measures of broader 

interest/impact with other relevant institutions such as EFSA, EPPO, EMSA, etc.; 

Promoting and supporting campaigns of eradication/control in emergency cases; 

Circulating general information on invasive species. 

The need to create a European agency has been stressed by Hulme et al., (2010). This paper 

called on Europe to establish a new European agency (European Centre for Invasive Species 

Management; ECISM) based on the experience of the European Centre for Disease Prevention 

and Control (ECDC). ECDC had an initial budget of € 4.8 millions, that has grown to € 90 

millions in 2010; EAIS budgetary level may be comparable to the costs foreseen for the initial 

phase of ECDC, with a permanent staff of about 30-40 people, organisation of working groups, 

and maintenance and updating of the information system, requiring a total budget significantly 

smaller than the average budget of other European agencies. On the basis of these 

considerations, the estimated budget of EAIS would thus be between 3 and 6 million €/year. As 

for all Community Agencies, EAIS should be financed by a Community subsidy (part of the 

costs may be also covered by hosting MS). 

Efficacy of the EAIS partly depends on the legislative approaches that will be adopted by the 

EU (implementing the Strategy on IAS). However, it is clear that the institutional role would 

enable the effective improvement in enforcing actions by national and European authorities. 

Moreover the establishment of specialised staff would ensure best use of synergies and technical 

ability in terms of EWRR. Indeed, permanent financial support would ensure the possibility to 

make best use of the available information systems and tools in the long term. It would also 

enable best internal coordination, networking and internal synergy. Increased synergy with other 

European institutions and structures would be also guaranteed as well as an improved interaction 

with other involved sectors (trade, tourism, agriculture, etc.). 

Option E: creating a EU biosecurity body 

As suggested by the experience of other countries and regions of the world (i.e. New Zealand) 

the most cost-effective option to reduce impacts of IAS is a framework merging sectors of the 

most relevant EU authorities involved in the issue, throughout a coordinated and comprehensive 

biosecurity policy centralised at the EU level. Such an ambitious approach would require a 

complex redesigning of the entire EC legal aquis, by re-designing of the entire existing legal 

framework regulating the different involved sectors (agriculture; plant, animal and human health; 

etc), with significant effects also in terms of national legislations. In addition, there are financial 

considerations that are worth mentioning. In fact, based on the figures available for New 

Zealand, where the biosecurity policy costs about 0.13% of the national GDP, and for Australia, 

where in 2007-2008 the quarantine framework has been estimated to account for about 0.07% of 

the national GDP (budget for the biosecurity activities in Australia approximately = AU$544 

millions; overall AU$ 793.4 billions) we can hypothesise that a EU biosecurity framework 

would require a budget in the order of magnitude of € 10 billions. Though apparently expensive, 

the rationale for considering such an option is that the costs for a EU biosecurity policy are well 

below the economic impacts caused by invasive species in the region (estimated to be over € 12 

billions/year; Kettunen et al., 2009). Moreover the budget needed to implement this biosecurity 

policy would not be an additional expense for Europe, but would largely rely on a optimised 



98

eallocation of the budget currently available in the health, agriculture and trade sectors (i.e. by 

promoting synergies and avoiding inconsistencies). 

An EU information system for early warning 

In order to guarantee a successful implementation of a sound EWRR system it is fundamental 

to develop and maintain a joint information system coordinated at both the EU and the 

national/local level to collect, analyse and exchange information on invasive alien species and 

related management strategies, so as to react to biological invasions more rapidly and effectively 

at the regional level. 

Such an information system should be characterised by a number of technical/scientific tools 

which should be available to the competent authorities to support the decision process for rapid 

detection and early warning of new invasions. Such decision support tools can be distinguished 

into the following main categories: 

1) Databases and inventories 

2) Experts register 

3) Species identification tools 

4) Alarm lists 

Additional tools which are fundamental for the implementation of a EWRR system are black 

and white lists (for a more detailed description of such tools see Shine et al., 2010), the legal 

instruments needed/available at the EU and local level, as well as all current financial tools. 

The information system and its components listed above need to be designed in a way that 

secures distributed efforts from all MSs and incorporates a coordinating function. A basic 

requirement is that the central coordinating body (i.e. the dedicated structure described below, 

possibly supported by an expert steered group) guarantees that all MSs participate in all aspects 

of developing and maintaining such a system (e.g. similarly to EEA and EIONET programme), 

so as to guarantee its long term sustainability. 

Many information tools that have already been developed in Europe and the rest of the world 

could provide support to the activities reported above, from species identification, to 

management options, to access to expertise. It is therefore crucial that any EU information 

system is linked to other existing information tools. 

Here follows a brief description of the 4 main decision support tools listed above. 

1) Databases and inventories 

The capacity to identify, prevent and mitigate IAS threats depends on accurate and updated 

information that is easily accessible at the right scale. This requires the creation/maintenance of a 

single EU portal for IAS information/interoperability of national IAS databases and inventories. 

Among the main information mechanism on IAS currently available at the regional level, the 

most comprehensive and updated are DAISIE and NOBANIS (see Conclusions §35 of the above 

mentioned 2953rd Environment Council meeting: ―establishment and maintenance of a 

comprehensive inventory of IAS which could be based on the DAISIE list of alien species in 

99 



Europe and other existing European inventories and mechanisms such as NOBANIS‖). A new 

database should be implemented, based on a common and agreed data shell, and on the 

integration of the information already made available by the DAISIE and NOBANIS projects. 

2) Experts register 

Decision making requires access to the most advanced scientific expertise on very different 

aspects, from the species taxonomy and biology (also for species not yet recorded in Europe), to 

management alternatives, to legal aspects. In this regard it is important to ensure the rapid 

involvement of key experts, to be contacted not only in Europe but also in the rest of the world. 

Contact details of experts should be readily available to competent authorities and all EWRR 

involved actors at national and regional levels (e.g. customs and quarantine services), i.e. by 

means of a comprehensive and updated expert registry. Such a contact list could be further 

developed and updated on the basis of the registry already produced by the DAISIE project. 

3) Species identification tools 

Correct taxonomic diagnosis of species is essential to respond to biological invasions. In this 

respect, the information system shall contain or include references/links to the most advanced 

tools to assist species identification. Species profiles should be populated with detailed 

descriptions, possibly including dichotomous keys, photographs, illustrations, etc. 

To enhance response to invasions, the information system should integrate information on the 

most effective and/or practicable management options to target new invaders. 

4) Alarm lists 

Central to an EWRR system is the prompt detection and identification of newly arrived alien 

species, and of the characterisation of alien species that are already present in Europe, but have 

not yet become invasive and/or widespread. A comprehensive and regularly updated species alert 

list (including information to be readily available for highest-risk IAS about host commodities; 

source regions; seasonal/environmental factors important for their introduction and 

establishment; and actual/potential pathways for their introduction) should be available to EU 

and national/local authorities. 

Coordinated surveillance and monitoring activities 

Monitoring and surveillance are fundamental activities to promptly report all records of alien 

species and to guarantee rapid response actions to prevent the establishment of newly-introduced 

IAS. 

Surveillance includes activities aimed at promptly identifying alien species new to the country 

and therefore is a pivotal element of prevention of further establishments. Dedicated surveillance 

programs should be established at entry points (i.e. point of import) where border controls and 

quarantine measures should be implemented in order to prevent or minimise the risk of 

introduction of alien species that are or could become invasive, or in particularly vulnerable 

areas, such as islands. Surveillance programs need to be implemented on a regional scale of 

action in order to guarantee an optimal efficacy. In this regard, it is important to launch a 

European surveillance system, policy involving all MSs, based on agreed priorities and common 

reporting standards, with the task of optimising use of existing capacity, involving key societal 

100 



sectors, promoting standardised procedures to collect, analyse and promptly circulate 

information on new incursions. An alarm list of key invasive species at risk of arrival can help to 

prioritise areas for surveillance. 

Monitoring programmes aim to acquire a better understanding of the ecology, distribution, 

patterns of spread and response to management of IAS, which are key elements to strengthen the 

capacity to predict the consequences of alien species introductions. Therefore monitoring 

programmes provide critical information to support IAS prevention, mitigation and restoration 

programmes and as such a stronger scientific basis for decision-making and allocation of 

resources. Thus it is clear that the ability of institutions and national governments to effectively 

respond to new incursions of alien species can be improved only by increasing the number of 

monitoring programs dedicated to invasive alien species. 

Monitoring programmes already exist in EU countries, e.g. further to the implementation of 

the Habitats and Birds directives. With regard to the alien species issue, it is necessary to bridge 

the gaps in taxonomy and environments not covered by existing programs, and ensure 

integration/coordination with other existing monitoring programs already focusing on native 

species. IAS-specific monitoring actions need to be prioritised, i.e. based on categorisation of 

threats, mapping of high-risk areas for incursions (scope for EU involvement in delimiting 

surveys). EU financial tools (LIFE+, Research Framework Programmes, etc) should support 

projects that respond to these criteria. 

An effective implementation of the surveillance and monitoring activities needs to rely on a 

clear definition of roles and responsibilities (focal points/competent authorities). For this reason, 

clear protocols for the identification of ―who is in charge of doing what‖ have to be developed, 

so as to prevent flaws in the information flow and allow a sound response to face the threat of 

new alien species entering a country. Notification and reporting procedures (what, how, to 

whom) could be based on the experience from other existing programmes (e.g. see the Habitats 

and Birds directives, Bern Convention, EPPO, etc.). 

In order to enable better coordination among national surveillance and monitoring efforts, 

national or taxonomic databases (e.g. DAISIE, NOBANIS) should be regularly updated with the 

information collected throughout surveillance and monitoring activities. It should be 

possible/necessary to link to existing monitoring programmes and indicators to acquire 

information available from other sources and ensure coherence with other policies (e.g. 

agriculture, transport, etc.). 

Risk analysis or quick screening? 

The data and information collected following the implementation of the surveillance and 

monitoring activities, need to be duly analysed and circulated to the competent authorities. For 

this reason, another fundamental element of the EWRR system is the risk analysis. The risk 

analysis represents the necessary step that builds on the information collected by the EU 

dedicated structure on a target alien species (before or soon after its introduction) and that leads 

to a decision on the actual measures which should be undertaken as a response action so as to 



101

prevent its introduction or its permanent establishment (e.g. eradication, control, regulation of 

trade, etc.). 

The assessment of the risks connected to the introduction of an alien species can be done at 

different levels of accuracy, depending on the objectives of the assessment: when deciding how 

to respond to a new incursion, a quick screening of the risks connected to the introduced species 

is in general more than sufficient to identify the proper response (Genovesi et al., 2010). When 

the exercise aims to prioritise action, or to support regulations of trade, then a full and 

comprehensive risk analysis is required (Genovesi et al., 2010). 

Therefore, whenever a new incursion is detected, a quick screening of the potential risks 

(based on available records of invasiveness in other situations, available information on 

ecological characteristics, etc.) should be promptly done, so as to provide a sufficient basis to 

decide how to react (for example in the case of detection of an organism included in the list of 

species with records of invasiveness elsewhere in Europe, eradication measures should be 

undertaken without further investigations). Basic elements to take into account when performing 

a quick screening on a species include: distribution (already widespread, present and invasive, 

localised, etc), species status (invasive in other European contexts, not yet present in Europe and 

invasive elsewhere, considered as low risk, etc) and biology (native range with similar climatic 

conditions to Europe, high spread potential, etc). The evaluation process should be as transparent 

as possible and based on concrete and documented but rapidly accessible information. 

In contrast, a risk analysis – in accordance with the IPPC terminology - is the process of 

evaluating biological or other scientific and economic evidence to determine whether an alien 

species will become invasive and, if so, how it should be managed. A risk analysis includes both 

risk assessment and risk management. The risk assessment is the comprehensive evaluation of 

the likelihood of entry, establishment or spread of an alien species in a given territory, and of the 

associated potential biological and economic consequences, taking into account possible 

management options that could prevent spread or impacts. The risk management is the 

evaluation and selection of options to reduce the risk of introduction and spread of an invasive 

alien species. Elements to be considered in a risk analysis include: objectives of the assessment, 

history of invasiveness of the taxon elsewhere, analysis of known pathogens or parasites, 

assessment of suitability of environmental conditions for persistence, probability of 

establishment and spread anywhere in the area of concern, potential impacts and available 

mitigation options. 

The result of a risk analysis should be given a formal/legal value so as to guarantee a 

consistent follow up (inclusion in black lists, endorsement of management measures, including 

control, eradication, regulation of trade, monitoring of introduced populations, etc.). In fact, the 

efficacy and consistency of a sound risk analysis (and quick screening) would be guaranteed 

only if done at a EU regional level (though considering the local situations and conditions) and 

the results jointly endorsed by all interested countries. A local approach might limit the actual 

impact of this exercise and would negatively affect any follow up in terms of response actions. 

Some European countries have already started regulating the movement/introduction of 

species on the basis of the results of detailed risk analysis. Therefore, a good number of best 

102 



practices are already available to this regard (e.g. EPPO, EFSA, UK Department for 

Environment, Food and Rural Affairs - DEFRA, etc.). 

Contingency planning and rapid response 

Once a new incursion is detected, and associated risks are preliminarily screened, it is crucial 

to decide promptly what measures have to be implemented (either eradication, control, 

containment or no action), what techniques have to be applied and who should enforce them. 

It is difficult to predict with any certainty the length of the critical period during which 

eradication is feasible after a species being introduced/detected in a new area. In fact, there is 

only a limited period of time in which eradication is a practicable option, before the invasive 

species reaches a certain level of population and/or range expansion. However, in order to reduce 

as far as possible the time between documenting an introduction and implementing a response, a 

clear allocation of roles and powers and the development of contingency plans for eradicating 

newly detected alien species should be guaranteed. 

To this purpose, all competent authorities (including local authorities and protected area 

authorities) should have sufficient powers to remove IAS or alien species with a high potential to 

become invasive, in accordance with national law and policy. The use of emergency orders 

should be also considered where urgent eradication action is needed. Contingency plans (preidentification 

of appropriate response) should be also considered so as to be ready to apply for 

eradicating groups of species with similar characteristics (e.g. plants, invertebrates, marine 

organisms, fresh-water organisms, fresh-water fishes, reptiles, amphibians, birds, small 

mammals, large mammals) and streamline the authorisation process for rapid response. 

Resource constraints make prioritisation necessary. Therefore mechanisms should be 

established in order to identify clear prioritisation of Community involvement, for example, the 

EC should be responsible (financially and technically) for the implementation of measures for 

major pests (listed in a EU black list), while for other pests the responsibility should be left to 

national/local authorities. For this reason, adequate funds and equipment for rapid response to 

new invasions as well as resources to train relevant staff to use the selected control methods, 

should be available. 

Follow up 

A final but essential element of the EWRR is reporting by the authorities in charge of the 

enforcing response actions. Such reporting addresses the progress of management measures and 

assesses their impact once the task is considered complete. Such reporting can allow a follow-up 

by the European technical structure and the European institutions, to inform other countries of 

the efficacy of the management options applied and to aid preparation should similar incursions 

occur elsewhere. 

This part of the communication flow is crucial to enable independent technical evaluation of 

the activities and a more transparent supply of information on progress to the entire community 

of states and stakeholders. 



103


We would like to thank all our friends and colleagues who provided valuable information and 

comments for the present work, among which Sarah Brunel, David Roy, Wojtek Solarz, plus 

many experts, particularly from the EEA, ISPRA, EPPO and the Invasive Species Specialist 

Group of the IUCN/SSC. This work is based on the results of a study financed by the EEA 

(Contract No. 3606/B2008/EEA.53386). 

Reference 

Genovesi P, Scalera R, Brunel S, Solarz W & Roy D (2010) Towards an early warning and information system for 

invasive alien species (IAS) threatening biodiversity in Europe. European Environment Agency, Tech. report 

5/2010. 52 pp. 

Hulme PE, Nentwig W, Pysek P, & Vilà M (2009) Common market, shared problems: time for a coordinated 

response to biological invasions in Europe? In: Pyšek, P. & Pergl, J. (Eds) (2009): Biological Invasions: 

Towards a Synthesis. Neobiota 8, 3–19 

Hulme PE, Pysek P, Nentwig W & Measures P (2010) Will Threat of Biological Invasions Unite the European 

Union? Science, 4-5. 

Kettunen M, Genovesi P, Gollasch S, Pagad S & Starfinger U (2009) Technical Support to EU Strategy on Invasive 

Alien Species (IAS) Assessment of the impacts of IAS in Europe and the EU. Institute for European 

Environmental Policy, London and Brussels. 

Shine C, Kettunen M, Genovesi P, Essl F, Gollasch S, Rabitsch W, Scalera R, Starfinger U, ten Brink P (2010) 

Assessment to support continued development of the EU Strategy to combat invasive alien species. Draft 

Final Report for the European Commission. Institute for European Environmental Policy (IEEP), Brussels, 

Belgium. 



104

European Environment Agency: Activities addressing invasive alien species 

Ahmet Uludag 

European Environment Agency, Kongens Nytorv 6, 1050 Copenhagen, Denmark 

E-mail: ahuludag@yahoo.com 

The European Environment Agency (EEA) assists the European Union and its Member States in 

designing effective tools to improve the environment, integrating environmental considerations 

into economic policies and moving towards sustainability. One key EEA task is coordinating the 

European environment information and observation network. In this context, EEA prepares 

reports, organizes outreach activities and develops tools and systems to assess the environment, 

mitigate harm and sustain ecosystem health. Invasive alien species (IAS) play an increasingly 

important role in EEA activities. IAS are considered the second most important threat to 

Europe‘s biodiversity after habitat fragmentation. Historically, EEA reports on the state of the 

environment have provided indications of IAS impacts on Europe‘s environment. The most 

recent report on the pan-European environment, the 2007 ‗Europe‘s Environment- The fourth 

assessment‘, provided more detailed information. IAS are among the indicators of threats to 

biodiversity in the SEBI 2010 (Streamlining European Biodiversity Indicators) indicator set. IAS 

are expected to acquire a more prominent role in future reporting processes. There is a political 

will to establish an early warning and rapid response system (EWRR) in Europe, as apparent in 

the European Commission‘s Communication COM(2008) 789 Final and Council conclusions in 

2009 (2988th Environment Council meeting, conclusions on international biodiversity beyond 

2010). On that basis, EEA is supporting efforts to establish an active and effective EWRR 

covering all EEA member and associate countries. 



105

Results of the survey on invasive alien plants in Mediterranean countries 

Giuseppe Brundu 1 , Italy, Guillaume Fried 2 , France, Sarah Brunel 3 

1 Department of Botany, Ecology ang Geology, University of Sassari, Italy 

E-mail: gbrundu@tin.it (Presenting author) 

2 Laboratoire National de la Protection des Végétaux, Station de Montpellier, CBGP, Campus 

International de Baillarguet, CS 30016, 34988 Montferrier-sur-Lez Cedex, France. 

E-mail : fried@supagro.inra.fr 

3 The European and Mediterranean Plant Protection Organization, 21 Bld Richard Lenoir, 

75011 Paris, France. 

E-mail: Brunel@eppo.fr 

A major step in tackling invasive alien plants consists of identifying those species that represent 

a future threat to managed and unmanaged habitats. The European and Mediterranean Plant 

Protection Organization reviews and organizes data on alien plants in order to build an early 

warning system. A survey has been launched prior to the workshop through the internet to any 

expert of the Mediterranean countries on plant considered invasive, elaboration of lists and 

sources of information used on the topic as well as eradication actions undertaken. The survey 

has received a good participation as about 30 answers were received from Armenia, Bulgaria, 

Croatia, France, Greece, Israel, Italy, Malta, Morocco, Portugal, Serbia, Spain, Tunisia, Turkey, 

as well as from California. 

Although in recent years there have been efforts to produce Europe-wide databases of invasive 

alien plants, these data sets have to main limits, i.e. they need continuous updating and they do 

not take into considerations many of the Countries facing the Mediterranean basin. 

The lists of invasive alien plants provided by the respondents will be aggregated to produce a 

overview of plants considered invasive in Mediterranean countries, although such meta list is not 

intended to be exhaustive. Within the EPPO framework, a prioritization system is being 

developed to select species that represent emerging threats and require the most urgent pest risk 

analysis to implement preventive measures and to perform eradication and management 

measures. So far, previous surveys and rapid assessments of spread and impact have allowed 

identification of emerging invasive alien plants for Mediterranean countries: Alternanthera 

philoxeroides (Amaranthaceae), Ambrosia artemisiifolia (Asteraceae), Baccharis halimifolia 

(Asteraceae), Cortaderia selloana (Poaceae), Eichhornia crassipes (Pontederiaceae), Fallopia 

baldschuanica (Polygonaceae), Hakea sericea (Proteaceae), Humulus japonicus (Cannabaceae), 

Ludwigia grandiflora and L. peploides (Onagraceae), Hydrilla verticillata (Hydrocharitaceae), 

Microstegium vimineum (Poaceae), Myriophyllum heterophyllum (Haloragaceae), Pennisetum 

setaceum (Poaceae), Pistia stratiotes (Araceae), Salvinia molesta (Salviniaceae) and Solanum 

elaeagnifolium (Solanaceae). Applying the prioritization process to the new meta list produced 

through the survey may allow identifying new emerging invasive alien plants. All respondents 

are invited to be associated to such task. 

The extraction of the information provided in the survey will also allow the elaboration of an 

inventory of plant eradication actions. Sharing knowledge and promoting existing initiative shall 

raise awareness on eradication, which although very effective remains too scarcely used in 

European and Mediterranean countries. 

106 



Molecular research as tool for managing biological invasions: Acacia saligna as a case 

study 

GD Thompson 1 *, JJ Le Roux 1 , DU Bellstedt 2 , DM Richardson 1 , JRU Wilson 1,3 

1 

Centre for Invasion Biology, Department of Botany and Zoology, Stellenbosch University, 

Matieland, 7602, South Africa. 

2 

Department of Biochemistry, Stellenbosch University, Matieland, 7602, South Africa 

3 

South African National Biodiversity Institute, Kirstenbosch National Botanical Gardens, 

Claremont 7735, South Africa. 

*Corresponding author: GD Thompson, Centre for Invasion Biology, Department of Botany and 

Zoology, Natural Sciences Building, Private Bag X1, University of Stellenbosch, Matieland, 

7602, South Africa. Genevieve.D.Thompson@gmail.com 

Introduction 

Molecular ecological approaches can inform ecologists about the introduction 

dynamics of invasive species, and potentially provide insight into effective 

management. Australian acacias are a widely distributed group of woody 

invaders of economic importance that are well represented in South Africa 

(RSA). We chose the Acacia saligna (Labill.) H. L. Wendl. species complex 

(four proposed subspecies native to Western Australia) as a case study, and 

used microsatellites to compare native and invasive populations. Our results 

suggest the presence of a novel genetic entity that has likely arisen due to 

cultivation of the species in RSA. Our findings provide support for A. saligna’s 

history of multiple introductions to RSA. Novel genotypes in the introduced 

range have often been linked to increased fitness in other invasive plant 

species; and may be incompatible with a single, specific natural enemy. We 

suggest that multiple introductions of biological control agents from across A. 

saligna‘s native range may enhance control via improved host specificity to the 

novel entity of A. saligna present in RSA. 

Determining how and why some species become major invaders can allow prediction of 

future invasions based on common ‗invasive‘ characteristics (Kolar & Lodge, 2001). Biotic 

characteristics and interactions (e.g. life history traits, intra-specific diversity and hybridization, 

Novak & Mack, 2005); and/or abiotic characteristics (e.g. invasion history, mode and purpose of 

introduction, Lockwood et al., 2007) can provide an indication of the invasive potential of a 

species. For instance, the introduction history of a species could influence the amount and 

structure of genetic diversity introduced to the new range (Le Roux et al. 2011). In the case of 

cryptic species, their introduction dynamics would significantly affect their invasive intraspecific 

diversity, the opportunity for intra-specific hybridization (e.g. Tamarix spp., Gaskin & 

Schall, 2002) or the development of novel genotypes or hybrids (e.g. Schinus terebinthifolius, 

Williams et al., 2005). 

Molecular research has been used as a tool for managing biological invasions to, among other 

things: reconstruct invasion histories (e.g. Prentis et al., 2009; Rollins et al., 2009; Bock et al., 

107 



2011); assess the role of sexual versus clonal reproduction in invasive spread (see Okada et al., 

2009); identify source populations (e.g. Baker & Dyer, 2011) and allocate resources to prevent 

further introductions (e.g. Frankham et al., 2005; Tang et al., 2009; Le Roux et al., 2011). The 

most common management recommendation in the recent literature has been to limit the 

dispersal of the introduced species, irrespective of the genetic signature (high, low or no genetic 

diversity) in the introduced range (Appendix, Gaskin et al., 2009; Okada et al., 2009; Prentis et 

al., 2009; Rollins et al., 2009; Tang et al., 2009; Bock et al., 2010; Baker & Dyer, 2011; Hsieh et 

al., 2011; Le Roux et al., 2011; Mendes et al., 2011). This was the case across a range of 

organisms (plant or insect) and breeding systems. However, a number of studies on invasive 

plants have suggested that high genetic diversity acts a driver of invasive success as a result of 

the large genetic base on which local selection can act (Ellstrand & Schierenbeck 2000, Mack et 

al., 2000; Lavergne & Molofsky, 2007). The literature shows that understanding the dynamics of 

species invasions, including the mode, pathway, site, source and number of introductions 

(Simberloff, 2009) has the potential to significantly enhance management approaches. 

Australian acacias and their molecular ecology 

There are 1,012 recognised Australian acacias (species in subgenus Phyllodineae that have 

Australia as part of their native range), of which around a third have been introduced to countries 

outside of Australia (Richardson et al., 2011). Several Australian Acacia species invade 

Mediterranean-type regions of the world, where they displace native biodiversity and 

considerably alter ecosystem structure and function (Macdonald et al., 1988, Richardson and 

Rejmánek, 2011). There are fourteen invasive acacias in South Africa (RSA) that have 

considerable negative effects on native biodiversity (van Wilgen et al., 2011; Wilson et al., 2011 

this volume). To obtain a global overview of these fourteen acacias, we collated records from the 

Global Biodiversity Information Facility (GBIF, 2010, http://www.gbif.org) and digitised their 

distributions at a global scale (Fig. 1a); and at a national scale in RSA (Fig. 1b). The global 

distributions clearly show that the Australian acacias that occur in RSA, also occur in several 

other Mediterranean-type regions around the globe (Fig. 1a). 

Invasive acacias in RSA represent a novel system where several different species have been 

introduced to a single region, ranging in number, timing, and mode of introduction (see Poynton, 

2009; Roux, 1961; Shaughnessy, 1980; van Wilgen et al. 2011). Their reason for introduction 

can be linked to the number of introductions and the species‘ invasive range size, i.e. 

silvicultural species are most commonly introduced on multiple occasions and are often widely 

dispersed. In addition, numerous microsatellite markers have been developed for acacias (A. 

saligna, A. mangium) (Butcher et al., 2000; Millar & Byrne, 2007) and their relatives (P. 

lophantha; Brown et al., 2011) and may be transferable to other species in the genus. 

Microsatellite markers enable fine-scale genetic processes to be quantified and compared at 

spatial scales. This provides opportunities to compare the genetic differences between the native 

and introduced range of Acacia species to their introduction dynamics, invasive intra-specific 

diversity and genetic population structure. In addition, several concepts in invasion biology can 

be concurrently tested including: novel genotypes, multiple introductions (or propagule 

pressure), and increased genetic diversity as stimuli of invasive success (Le Roux and 

Wieczorek, 2009). Thus, acacias in RSA provide an appropriate biological system to test the 

influence of a species‘ introduction history on its genetic signature in the introduced range. 



108

Figure 1 - Global distribution of fourteen Acacia species classified as major invaders in South 

Africa (van Wilgen et al., 2011) based on records from the Global Biodiversity Information 

Facility (GBIF, 2010, http://www.gbif.org). Their distributions are represented (a) at a global 

scale in their native (green circles) and introduced ranges (red circles), and (b) in their 

introduced range in South Africa. Occurrences for A. saligna in South Africa are represented 

by red crosses. 

In order to select an Australian acacia species for a population genetic study, we collated 

information on the introduction history of the fourteen invasive acacias in RSA, and their 

109 



anthropogenic uses (Table 2). Generally, the introduction history of a species can be associated 

with a distinct genetic signature, and the latter can be used as a proxy for introduction history for 

those species with poor historical records. The primary purpose of introduction of the fourteen 

major Acacia invaders to RSA varies from silviculture to dune stabilisation. Table 2 lists the 

fourteen major invaders, their purpose and date of introduction (Poynton, 2009), their invasive 

range sizes in quarter-degree grid squares (QDGS) (Henderson, 2001; Wilson et al., 2007) and 

whether they were introduced on multiple or single occasions (Poynton, 2009). Despite the fact 

that Acacia saligna occupies a relatively small range in RSA (160 QDGS, Appendix), it is still 

considered one of the most problematic, and highly abundant (see Fig. 1b, red crosses) invasive 

plant species in the Cape Floristic Regions (Macdonald & Jarman, 1984; Nel et al., 2004; 

Yelenik et al., 2004; Richardson et al., 1992). 

Table 2 - Fourteen major invasive Acacia species occurring in South Africa. Details of the 

introduction histories are given as the purpose and year of introduction, as well as their invasive 

range size in South Africa. 

Species φ Reason for introduction Date 

Multiple 

introductions † 

Invasive 

range size* 

Acacia baileyana ornamental 1919 yes 87 

Acacia cyclops dune stabilisation 1835 yes 167 

Acacia dealbata silviculture 1858 yes 256 

Acacia decurrens silviculture 1880 yes 101 

Acacia elata ornamental 1904 yes 38 

Acacia implexa unknown c. 1880 unknown 3 

Acacia longifolia dune stabilisation 1827 yes 95 

Acacia mearnsii silviculture 1858 yes 432 

Acacia melanoxylon silviculture 1848 yes 138 

Acacia paradoxa unknown c. 1850 unknown 1 

Acacia podalyriifolia ornamental 1894 yes 56 

Acacia pycnantha dune stabilisation, tanbark 1865 yes 35 

Acacia saligna dune stabilisation, tanbark 1833 yes 160 

Acacia stricta 

Note: 

unknown ? unknown 2 

* Invasive range size is a crude estimate, and is based on the number of quarter-degree grid cells 

occupied by each species (Henderson et al., 2001; Wilson et al., 2007). One quarter-degree grid 

cell is equal to approximately 25 km 2 . 

φ 

van Wilgen et al., 2011. 

ý Poynton, 2009. 

Acacia saligna 

As a case study, we chose the Acacia saligna (Labill.) H. L. Wendl. species complex because 

it has been introduced on multiple occasions and has been widely dispersed in RSA (Henderson, 

2001). Genetic research has been conducted in the native range (see George et al., 2006; Millar 

et al., 2008) providing the molecular markers for further research in RSA and other 

Mediterranean-type climates. Several management approaches for Acacia saligna are currently 

in place in RSA, including mechanical (Holmes et al., 1987), chemical and biological control 

110 



(Wood & Morris, 2007). For a general review on Australia acacia management see Wilson et al. 

(2011). 

The A. saligna species complex (four subspecies) is native to Western Australia (WA) 

(Maslin, 2004) and contributes to the invasion of several million hectares of RSA by invasive 

woody species (van Wilgen et al., 2001). It is also considered invasive in several other 

Mediterranean regions including California, Israel, Italy, France, Greece, Portugal and Spain 

(ILDIS, 2010). The taxonomy of the A. saligna species complex is complicated (Le Houerou & 

Pontanier, 1987; Maslin & McDonald, 2004; Millar et al., 2008; Millar et al., 2011). 

Furthermore, field identification of the subspecies of A. saligna by both managers and scientific 

researchers is problematic as only a few distinguishing morphological features are present 

(Maslin & McDonald, 2004). 

We aim to use population genetics to determine the number of genetic lineages and spatial 

genetic structure of A. saligna in RSA and native WA. In doing so we would like to reconstruct 

A. saligna‘s known introduction history, identify possible source populations, and assess intraspecific 

diversity in RSA. 

Materials and Methods 

Phyllode material was collected from individuals of A. saligna from across native Western 

Australia (WA) and invasive RSA. A total of 12 populations were sampled, 8 populations from 

WA, and 4 populations from RSA. Genomic DNA was extracted following the methods of 

Millar et al. (2008). Ten nuclear microsatellite loci previously developed for A. saligna (Millar 

& Byrne, 2007) were PCR-amplified following methods described by Millar and Byrne (2007). 

Microsatellite loci were genotyped, and the allele sizes were visualized and scored using 

GENEMAPPER version 3.4 (Applied Biosystems, Foster City, USA). 

GENALEX v 6.2 (Peakall & Smouse, 2006) was used to permute a co-variance standardized 

Principle Coordinate Analysis (PCoA) to determine the extent of population genetic structure 

between native and invasive populations. We used FSTAT 293 (Goudet, 2001) to test for 

statistical differences in genetic diversity indices: allelic richness (RS), unbiased gene diversity 

(HS) between native and invasive ranges. RSA individuals were assigned to the reference 

populations linked to each subspecies identified in the native range by Millar et al., (2011) using 

Bayesian methods in STRUCTURE v 2.3.2 (Pritchard et al., 2000; Falush et al., 2007). We 

assumed independence among loci, allowed admixture and computed 100,000 iterations, 

following a burn-in period of 10,000 for each value of K (number of populations) (Pritchard et 

al., 2000). Delta K (ΔK) was calculated according to the method of Evanno et al. (2005). 

Results 

Using the reference populations from Millar et al. (2011), Bayesian methods did not assign 

any introduced South African populations to any native populations collected in the study (Fig. 

2). Furthermore, Bayesian methods clustered all native populations into three groups, consistent 

with the genetic groups identified in Millar et al. (2011) (Fig. 2). At the population level, and 

consistent with the Bayesian analysis, the PCoA indicated that all native and invasive 

111 



populations were grouped into four separate groups (Fig. 2a). The first two axes of the PCoA 

explained 66% of the total genetic variance, with PC1 explaining 43% and PC2 explaining 23% 

of the variation, respectively. The PCoA identified 1 invasive cluster, and 2 native clusters (Fig. 

2a). The first cluster comprised all invasive populations from RSA (diamonds, Fig. 2a). The 

second cluster comprised 4 native populations: 2 populations representative of A. saligna 

subspecies lindleyi (triangles, Fig. 2a) and 2 populations representative of A. saligna subspecies 

stolonifera (squares, Fig. 2a). The third cluster comprised 4 native populations: 2 populations 

representative of A. saligna subspecies saligna and 2 populations representative of A. saligna 

subspecies pruinescens (circles, Fig. 2). Analyses of genetic diversity showed that Western 

Australia had marginally higher allelic richness and gene diversity (2.048 and 0.474 

respectively) compared to RSA (1.981 and 0.477 respectively, Fig 2b). 

Discussion 

The fourteen major Acacia invaders considered here cover a large area in RSA and several 

other Mediterranean-climate regions. The largest introduced range size in RSA is for those 

species that were introduced for silviculture, supporting the conjecture that economically 

valuable species are usually introduced on multiple occasions, locations, and in high numbers 

(propagule pressure). Species that were introduced for dune stabilisation and not simply for 

economic purposes (i.e. A. cyclops, A. longifolia, and A. saligna) are also subject to several 

management approaches, and this may also account for smaller range sizes compared to those 

species introduced for silviculture (e.g. A. dealbata and A. mearnsii). 

Comparative analyses of native and invasive populations of A. saligna show that invasive 

populations are comprised of genetic entities different to those present in the native range. 

Further that the introduced range has lower levels of genetic diversity compared to the native 

range. This suggests that A. saligna‘s history of multiple, sympatric introductions may have 

potentially facilitated novel genetic combinations over the ca. 170 years since its introduction; 

and that founder events followed by drift may have altered the species‘ invasive genetic diversity 

and structure. Indeed, reduced levels of genetic diversity in introduced populations of A. saligna 

in RSA have been reported compared to Australian populations (Le Roux et al., 2011). We 

speculate that genetic drift, followed by intensive cultivation of the species in RSA has 

facilitated the evolution of the novel genetic entity in RSA. These results are consistent with A. 

saligna’s history of extensive and widespread cultivation and planting in RSA. 

Management implications 

Correct identification of the subspecies of A. saligna is necessary to collate prior species 

knowledge for the development of management strategies. Generally management plans treat an 

introduced species as a single genetic entity (Regan et al. 2005) i.e. possessing similar genetic 

diversity to the native range. Considering A. saligna‘s problematic field identification (at the 

subspecies level), reduced levels of genetic diversity, and the presence a novel genetic entity in 

RSA, implications of our findings for management should be considered. 

The success of biological control programmes is largely dependent on the host-specificity of 

biological control agents (Blossey & Nötzold, 1995; Schaffner, 2001; Goolsby et al., 2006b). A 

number of studies have employed molecular methods to identify damaging natural enemies by 

112 



matching native and introduced populations of a weed at a subspecific level (e.g. shoot bud gall 

on Melaleuca quinquenervia, Giblin-Davis et al. 2001; a rust on blackberry Evans et al. 2005). 

Novel hybrids are problematic as they have no co-evolutionary history with potential control 

agents (insects or diseases). 

Figure 2 - Clustering of native and introduced populations of Acacia saligna using a) covariance 

standardized Principle Coordinate Analysis (PCoA); and b) the geographical 

distribution of the same populations assigned to genetic groups using Bayesian methods in 

their native range in Western Australia and their introduce range in South Africa. Bayesian 

methods identified four separate genetic clusters in the native and introduced range: three in 

Western Australia (circles, triangles and squares), and one in South Africa (diamonds). 

Introduced populations displayed reduced levels of genetic diversity (allelic richness and gene 

diversity) compared to the native range. 



113

Acacia saligna has been subject to several types of management in RSA (Rouget et al., 2003; 

Richardson & Kluge, 2008). A gall-forming rust fungus, Uromycladium tepperianum (Sacc.) 

McAlpine, and a seed-eating weevil, Melanterius servulus (Impson et al., 2004) have proved 

useful in controlling A. saligna’s spread (Wood & Morris, 2007). Considering the novel entity of 

A. saligna present in RSA, it is unlikely that the current native control agents will be sufficiently 

host-specific to RSA populations of A. saligna i.e. it is unlikely that any native biological control 

agent will be effective against a novel form of A. saligna (e.g. Casuarina spp., Gaskin et al., 

2009). 

Other cases of new genotypic combinations in invasive species coupled with multiple 

introductions and its implications for biocontrol have been documented (e.g. Goolsby et al., 

2006a; Gaskin et al., 2009; Prentis et al., 2009). Given the novel entity of A. saligna in RSA, and 

the diversity of Uromycladium species in A. saligna’s native range (Old et al., 2002); we 

speculate that multiple introductions of U. tepperianum (increased genetic diversity) to RSA may 

provide increased host specificity, and increased overall control efficacy. From a mechanical and 

chemical control perspective, management should consider the strong propensity of the native 

intra-specific variants of A. saligna towards vegetative reproduction via suckering. 

Our study, and numerous others (Gaskin et al., 2009; Okada et al., 2009; Prentis et al., 2009; 

Rollins et al., 2009; Tang et al., 2009; Bock et al., 2010; Baker & Dyer, 2011; Hsieh et al., 2011; 

Le Roux et al., 2011; Mendes et al., 2011) have shown the value of molecular research in the 

development of management strategies for invasive species. The molecular tools developed for 

A. saligna, and the genetic information presented herein may prove to be useful in other regions 

where A. saligna (or other invasive plants) is known to occur, e.g. in the Mediterranean. 


The authors would like to sincerely thank the European Weed Research Society who funded 

the travel for G.D. Thompson to attend the workshop in Trabzon, Turkey. We would also like to 

acknowledge the DST-NRF Centre for Invasion Biology, the Working For Water Programme, 

and Stellenbosch University for financial support for this research. 

References 

Baker SA, RJ Dyer (2011) Invasion genetics of Microstegium vimineum (Poaceae) within the James River Basin of 

Virginia, USA. Conservation Genetics. 

Bock DG, Zhan A, Lejeusne C, MacIsaac HJ and Cristescu ME (2011) Looking at both sides of the invasion: 

patterns of colonization in the violet tunicate Botrylloides violaceus. Molecular Ecology, 20, 503-516. 

Brown GK, Gardner MG (2010) Isolation, characterisation and transferability of microsatellites for Paraserianthes 

lophantha, Cape Wattle (Leguminosae: Mimosoideae): a significant weed worldwide. Muelleria, 29, 87-92. 

Blossey B & Nötzold R (1995) Evolution of increased competitive ability in invasive non-indigenous plants: a 

hypothesis. Journal of Ecology, 83, 887-889. 

Butcher P, Decroocq S, Gray Y, Moran G (2000) Development, inheritance and cross-species amplification of 

microsatellite markers from Acacia mangium. Theoretical Applied Genetics, 101:1282-1290. 

Ellstrand NC and Schierenbeck KA (2000) Hybridization as a stimulus for the evolution of invasiveness in plants? 

PNAS, 97, 7043-050. 

Evanno G, Regnaut S & Goudet J (2005) Detecting the number of clusters of individuals using the software 

STRUCTURE: A simulation study. Molecular Ecology, 14, 2611-2620. 

Evans KJ, Jones MK and Roush RT (2005) Susceptibility of invasive taxa of European blackberry to rust disease 

caused by the uredinial stage of Phragmidium violaceum under field conditions in Australia. Plant 

Pathology, 54, 275-286. 



114

Falush D, Stephens M & Pritchard JK (2007) Inference of population structure using multilocus genotype data: 

Dominant markers and null alleles. Molecular Ecology Notes, 7, 574-578. 

Frankham R (2005) Resolving the genetic paradox in invasive species. Heredity, 94, 385. 

Gaskin JF, Wheeler GS, Purcell MF and Taylor GS (2009) Molecular evidence of hybridization in Florida‘s sheoak 

(Casuarina spp.) invasion. Molecular Ecology, 18, 3216-3226. 

Gaskin JF and Schaal BA (2002) Hybrid Tamarix widespread in US invasion and undetected in native Asian range. 

PNAS, 99, 11256-11259. 

George N, Byrne M, Maslin B, & Yan G (2006) Genetic differentiation among morphological variants of Acacia 

saligna (Mimosaceae). Tree Genetics and Genomes, 2, 109-119. 

Giblin-Davis RM, Makinson J, Center BJ et al. (2001) Fergusobia/Fergusonina- induced shoot bud gall 

development on Melaleuca quinquenervia. Journal of Nematology, 33, 239-247. 

Goolsby JA, De Barro PJ, Makinson JR, Pemberton RW, Hartley DM & Frohlicj DR (2006a) Matching the origin of 

an invasive weed for the selection of a herbivore haplotype for a biological control programme. Molecular 

Ecology, 16, 287-297. 

Goolsby JA, van Klinken RD and Palmer WA (2006b) Maximising the contribution of native-range studies towards 

the identification and prioritisation of weed biocontrol agents. Australian Journal of Entomology, 45, 276- 

286. 

Goudet J (2001) Fstat: A program to estimate and test gene diversities and fixation indices version 2.9.3.2 updated 

from Goudet 1995. 

Hsieh CH, Chiang YH and Ko CC (2011) Population genetic structure of the newly invasive Q biotype of Bemisia 

tabaci in Taiwan. Entomologia Experimentalis et Applicata, 138, 263-271. 

Henderson L (2001) Alien weeds and invasive plants. ARC-PPRI, PPRI Handbook No. 12, Pretoria, South Africa. 

Holmes PM, Macdonald IAW & Juritz J (1987) Effects of clearing treatment on seed banks of the alien invasive 

shrubs Acacia saligna and Acacia cyclops in the southern and south-western Cape, South Africa. Journal of 

Applied Ecology, 24, 1045-51. 

ILDIS (2010) International Legume Database and Information Service, July 2010. [http://www.ildis.org]. 

Impson FAC, Moran VC & Hoffmann JH (2004) Biological control of an alien tree, Acacia cyclops, in South 

Africa: Impact and dispersal of a seed-feeding weevil, Melanterius servulus. Biological Control, 29, 375- 

381. 

Kolar CS & Lodge DM (2001) Progress in invasion biology: Predicting invaders. Trends in Ecology and Evolution, 

16, 199-204. 

Lavergne S & Molofsky J (2007). Increased genetic variation and evolutionary potential drive the success of an 

invasive grass. Proceedings of the National Academy of Science USA, 104, 3883-3888. 

Le Houerou HN & Pontanier R (1987) Silvopastoral plantations in the arid zone of Tunisia. MAB Tech Notes, 18, 

81. 

Le Roux JJ, Geerts S, Ivey P, Krauss P, Richardson DM, Suda J, Wilson JRU (2010) Molecular systematics and 

ecology of invasive Kangaroo Paws in South Africa: management implications for a horticulturally 

important genus. Biological Invasions, 12, 3989-4002. 

Le Roux JJ, Wieczorek AM (2009) Molecular systematics and population genetics of biological invasions: towards 

a better understanding of invasive species management. Annals of Applied Biology, 154, 1-17. 

Le Roux JJ, Brown G, Byrne M, Ndlovu J, Richardson DM, Thompson GD & Wilson JRU (2011) Phylogeographic 

consequences of different introduction histories of invasive Australian Acacia species and Paraserianthes 

lophantha (Fabaceae) in South Africa. Diversity and Distributions, 17, 861-871. 

Lockwood JL, Hoopes MF & Marchetti MP (2007) Invasion Ecology. Blackwell Publishing, Oxford. 

Macdonald IAW & Jarman ML (1984) Invasive alien organisms in the terrestrial ecosystems of the fynbos biome, 

South Africa. In: South African National Science Progress Report No. 85, CSIR, Pretoria. 

Macdonald IAW, Graber DM, De Benedettii S, Groves RH & Fuentes ER (1988) Introduced species in nature 

reserves in Mediterranean-type climatic regions of the world. Biological Conservation, 44, 37-66. 

Mack RN, Simberloff D, Lonsdale WM, Evans H, Bazzaz FA. (2000) Biotic invasions: causes, epidemiology, 

global consequences and control. Ecological Applications, 10, 689-710. 

Mendes MD, Lima SA, Trindade H, Correia AID, Barrosao JG, Pedro LG, Figueiredo CA. (2011) ISSR molecular 

characterization and leaf volatiles analysis of Pittosporum undulatum Vent. naturalized in the Azores 

archipelago (Portugal), Industrial Crops and Products, 33, 710-719. 

Maslin BR & McDonald MW (2004) Acacia search. Evaluation of Acacia as a woody crop option for southern 

Australia. RIRDC Report 03/017. Rural Industries Research and Development Corporation, Canberra. 



115

Millar MA, Byrne M & O‘Sullivan W. (2011) Defining entities in the Acacia saligna (Fabaceae) species complex 

using a population genetics approach. Australian Journal of Botany, 59, 137-148. 

Millar MA & Byrne M (2007) Characterization of polymorphic microsatellite DNA markers for Acacia saligna 

(Labill.) H.L.Wendl. (Mimosaceae). Molecular Ecology Notes, 7, 1372-1374. 

Millar MA, Byrne M, Nuberg I & Sedgley M (2008) A rapid PCR-based diagnostic test for the identification of 

subspecies of Acacia saligna. Tree Genetics and Genomes, 4, 625-635. 

Nel JL, Richardson DM, Rouget M, Mgidi TN, Mdzeke N, Le Maitre DC, Van Wilgen BW, Schonegevel L, 

Henderson L and Neser S (2004) A proposed classification of invasive alien plant species in South Africa: 

Towards prioritizing species and areas for management action. South African Journal of Science, 100, 53- 

64. 

Novak SJ & Mack RN (2005) Genetic bottlenecks in alien plant species: Influence of mating systems and 

introduction dynamics. Species invasions: Insights into ecology, evolution and biogeography (ed. by Sax 

DF, Stachowicz JJ & Gaines SD), pp. 201-228. Sinauer, USA. 

Old KM, Vercoe TK, Floyd RB, Wingfield MJ, Roux J, Neser S (2002) Acacia spp: FAO/IPGRI technical 

guidelines for the safe movement of germplasm no. 20. International Plant Genetic Resources Institute, 

Rome. 

Okada M, Grewell BJ and Jasieniuka M (2009) Clonal spread of invasive Ludwigia hexapetala and L. grandiflora in 

freshwater wetlands of California, Aquatic Botany, 91, 123-129. 

Peakall R & Smouse PE (2006) Genalex 6: Genetic analysis in excel. Population genetic software for teaching and 

research. Molecular Ecology Notes, 6, 288-295. 

Poynton, RJ (2009) Tree Planting in Southern Africa, Volume 3. Acacia and other species. Pretoria: Department of 

Forestry. 

Prentis PJ, Sigg DP, Raghu S, Dhileepan K, Pavasovic A and Lowe AJ. (2009) Understanding invasion history: 

genetic structure and diversity of two globally invasive plants and implications for their management. 

Diversity and Distributions, 15, 822-830. 

Pritchard JK, Stephens M & Donnelly P (2000) Inference of population structure using multilocus genotype data. 

Genetics, 155, 945-959. 

Regan HM, Ben-Haim Y, Langford B, Wilson WG, Lundberg P, Andelman SJ & Burgman MA (2005) Robust 

decision-making under severe uncertainty for conservation management. Ecological Applications, 15, 

1471-1477. 

Richardson DM, Carruthers J, Hui C, Impson FAC, Miller JT, Robertson MP, Rouget M, Le Roux JJ and Wilson 

JRU (2011) Human-mediated introductions of Australian acacias—a global experiment in biogeography. 

Diversity and Distributions, 17, 771-787. 

Richardson DM & Rejmánek M (2011) Trees and shrubs as invasive alien species – a global review. Diversity and 

Distributions, 17, 788-809. 

Richardson DM & Kluge RL (2008) Seed banks of invasive Australian Acacia species in South Africa: Role in 

invasiveness and options for management. Perspectives in Plant Ecology, Evolution and Systematics, 10, 

161-177. 

Richardson DM, Macdonald IAW, Holmes PM & Cowling RM (1992) Plant and animal invasions. In: Cowling, 

R.M. (ed) The ecology of fynbos: Nutrients, fire and diversity, pp. 271-308. Oxford University Press, Cape 

Town. 

Rollins LA, Woolnough AP, Wilton AN, Sinclair R and Sherwin WB (2009) Invasive species can't cover their 

tracks: using microsatellites to assist management of starling (Sturnus vulgaris) populations in Western 

Australia. Molecular Ecology, 18, 1560-1573. 

Rouget M, Richardson DM, Cowling RM, Lloyd JW, Lombard AT (2003) Current patterns of habitat transformation 

and future threats to biodiversity in terrestrial ecosystems of the Cape Floristic Region, South Africa. 

Biological Conservation 112, 63 - 85. 

Roux ER (1961) History of the introduction of Australian Acacias on the Cape Flats. South African Journal of 

Science, 57, 99 -102. 

Schaffner U (2001) Host range testing of insects for biological weed control: how can it be better interpreted? 

BioScience, 51, 951-959. 

Shaughnessy GL (1980) Historical ecology of alien woody plants in the vicinity of Cape Town, South Africa. 

University of Cape Town, Cape Town. 

Simberloff D (2009) The role of propagule pressure in biological invasions. Annual Review of Ecology, Evolution, 

and Systematics, 40, 81-102. 



116

Tang SQ, Wei F, Zeng, LY, Li XK, Tang SC, Zhong Y and Geng YP (2009), Multiple introductions are responsible 

for the disjunct distributions of invasive Parthenium hysterophorus in China: evidence from nuclear and 

chloroplast DNA. Weed Research, 49, 373-380. 

van Wilgen BW, Dyer C, Hoffmann JH, Ivey P, Le Maitre DC, Richardson DM, Rouget M, Wannenburgh A & 

Wilson JRU (2011) A strategic approach to the integrated management of Australian Acacia species in 

South Africa. Diversity and Distributions, 17, 1060-1075. 

van Wilgen BW, Richardson DM, Le Maitre DC, Marais C & Magadlela D (2001) The economic consequences of 

alien plant invasions: examples of the impacts and approaches to sustainable management in South Africa. 

Environment, Development and Sustainability, 3, 145-168. 

Williams DA, Overholt WA, Cuda JP and Hughes CR (2005) Chloroplast and microsatellite DNA diversities reveal 

the introduction history of Brazilian peppertree (Schinus terebinthifolius) in Florida. Molecular Ecology, 

14,3643-3656. 

Wilson JR, Kaplan HJ, Mazibuko D, de Smidt J, Zenni RD and van Wyk E (2011) Eradication and monitoring of 

Australian acacias in South Africa as part of an EDRR program. This volume. 

Wilson JRU, Gairifo C, Gibson MR, Arianoutsou M, Bakar BB, Baret S, Celesti-Grapow L, Dufour-Dror JM, 

Kueffer C, Kull CA, Hoffmann JH, Impson FAC, Loope LL, Marchante E, Marchante H, Moore JL, 

Murphy D, Pauchard A, Tassin J, Witt A, Zenni RD & Richardson DM (2011) Risk assessment, 

eradication, containment, and biological control: global efforts to manage Australian acacias before they 

become widespread invaders. Diversity and Distributions, 17, 1030-1046Wilson JRU, Richardson DM, 

Rouget M, Procheş S, Amis MA, Henderson L & Thuiller W (2007) Residence time and potential 

range: crucial considerations in modelling plant invasions. Diversity and Distributions, 13, 11-22. 

Wood AR & Morris MJ (2007) Impact of the gall-forming rust fungus Uromycladium tepperianum on the invasive 

tree Acacia saligna in South Africa: 15 years of monitoring. Biological Control, 41, 68-77. 

Yelenik SG, Stock WD & Richardson DM (2004) Ecosystem level impacts of invasive Acacia saligna in the South 

African fynbos. Restoration Ecology, 12, 44-51. 



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Appendix - Summary of recent literature combining molecular ecology and invasive species management. * Citations: 1) 

Mendes et al., 2011; 2) Hsieh et al., 2011; 3) Baker & Dyer, 2011; 4) Le Roux et al., 2011; 5) Bock et al., 2010; 6) Rollins et 

al., 2009; 7) Prentis et al., 2009; 8) Okada et al., 2009; 9) Gaskin et al., 2009; 10) Tang et al., 2009. 

Organism * Form 

Pittosporum 

undulatum 1 

Bemisia tabaci 2 

Microstegium 

vimineum 3 

tree 

Anigozanthos sp. 4 herb 

Botrylloides 

violaceus 5 

insect, 

agricultural pest 

Native 

range 

south-east 

Australia 

Possibly 

India 

grass Asia 

marine 

invertebrate 

Western 

Australia 

Northwest 

Pacific, 

Japan 

Introduced 

range 

Arores 

Archipelago, 

Portugal 

Global 

eastern United 

States 

Marker 

ISSRs 

cpDNA, 

SSRs 

AFLPs 

South Africa cpDNA 

Coasts of North 

America, 

Australia, Italy, 

UK, Ireland, 

Netherlands 

cpDNA, 

SSRs 

Sturnus vulgaris 6 bird Eurasia Global SSRs 

Macfadyena 

unguis-cati 

and Jatropha 

gossypiifolia 7 

plants Neotropics Global SSRs 

Introduced genetic 

signature 

High genetic 

diversity 

Relatively low 

genetic diversity 

and low population 

structure 

Variable- high and 

low genetic 

diversity 

Genetic diversity 

based on genome 

sizes 

Low genetic 

diversity but high 

population structure 

High genetic 

diversity 

M. unguiscati 

(single 

haplotype); 

J. gossypiifolia high 

genetic diversity 



Management recommendation 

Develop commercial use for species 

to reduce its spread. 

Limit dispersal of the species among 

greenhouses in the region 

Focus on limiting dispersal between 

populations in close proximity due 

to diffusive spread of the species. 

Trade in South Africa should be 

restricted, subject to the outcome of 

detailed risk assessments. 

Limit dispersal of asexual 

propagules via aquaculture practices. 

Long-term genetic monitoring to 

assess dispersal, changes in 

population size and effectiveness of 

control. 

M. unguis-cati: locally adapted 

natural enemies should make the 

best control agents. 

J. gossypiifolia: high genetic 

diversity suggests selection of biocontrol 

agents will be complex 

118

Ludwigia 

hexapetala and L. 

grandiflora 8 

aquatic plant 

South 

Mexico and 

South 

America 

Casuarina sp. 9 tree Australia 

Parthenium 

hysterophorus 10 

herb 

Tropical and 

subtropical 

America 

California, 

United States 

Florida, United 

States 

China, 

Australia, 

India, Africa 

AFLPs 

AFLPs 

cpDNA 

No genetic 

diversity due to 

clonal reproduction 

Hybridisation 

giving rise to novel 

hybrids 

High genetic 

diversity 



Target vegetative dispersal and 

growth 

Novel hybrids have no 

coevolutionary history with any 

insects or diseases, which may be 

problematic for biological control 

efforts. 

International and domestic 

quarantine to prevent new 

introductions, hybridisation and /or 

gene flow. 

119

Prioritization of Potential Invasive Alien Plants in France 

Guillaume Fried 

LNPV, CBGP, Campus International de Baillarguet, CS 30016, 34988 Montferrier-sur-Lez 

Cedex, E-mail : fried@supagro.inra.fr 

Introduction 

Given the number of alien species already present in France and the time 

needed to conduct a full pest risk analysis (PRA), a prioritization process 

appears to be a useful tool for a preliminary selection step. Existing 

screening processes often lack considerations about the technical feasibility 

of control and the current distribution of the species which are necessary to 

make a decision concerning eradication. The author therefore applied the 

latest version of the Prioritization Process developed by the European and 

Mediterranean Plant Protection Organization (EPPO PP) on a selection of 

303 alien species occurring in France or already invasive in neighboring 

countries. In a first step, this process classifies species into four categories: 

species not considered invasive, species on an observation list, potential 

invasive species and invasive species. A second step was to select those 

which are priority for a PRA from those already identified as potential and 

invasive species. 

This paper compares the results with those provided by the risk assessment 

system developed by Weber & Gut (Journal for Nature Conservation 12 

(2004) 171-179). This latter identifies three risk classes according to 

species scores based on their attributes and their environmental impact: low 

(3-20), intermediate (21-27) and high risk (28-39). Overall both methods 

yield similar results except for agricultural weeds which are not taken into 

account by Webber & Gut. Solidago canadensis (38), Acacia dealbata (36), 

Baccharis halimifolia (31) or Reynoutria japonica (34) were identified 

among the species with the highest risk. These species are also considered 

invasive by the EPPO PP but they are already too widespread for the 

outcomes of the PRA to be worthwhile. The advantage of the EPPO PP is 

that it makes it possible to identify among species with high impact, 

emergent invasive (or potential invasive) species for which preventive 

action will be most profitable in France, e.g. Alternanthera philoxeroides, 

Eriochloa villosa, Humulus japonicus, Myriophyllum heterophyllum. 

The management of invasive alien plant species usually focuses on species already widely 

distributed, with negative impacts on ecosystems (e.g. in France: Ludwigia grandiflora, 

Reynoutria japonica, Ambrosia artemisiifolia). This is of course necessary, but not sufficient 

since new plant species are regularly introduced with the globalization of trade. In order to 

tackle the fraction of the new introduced species that have a high probability to become 

widely established and invasive, we need to develop a more global strategy including early 

detections and preventive eradications in parallel to regular management actions. 

One important part of such preventive strategies includes Weed Risk Assessments (WRA) 

which are science-based risk analysis tools for determining the weed potential of new species 



120

introduced or detected on the territory. To develop an effective WRA-based strategy, we 

should first have a clear understanding of all alien species established on the national territory 

and be able to rapidly detect new arrivals on this territory. This means developing a national 

inventory of alien species that should be regularly updated (Genovesi & Shine, 2002) as well 

as an early detection system. 

Lists of alien plant species in France 

To date, despite a lot of existing information on invasive alien species e.g., the review of 

the current state of knowledge by Muller (2004), there is no comprehensive list of alien 

plants in France. Yet, these national inventories are widely recognized as providing a crucial 

source of information and are an important tool for invasion research and management 

(Cadotte et al. 2006; Richardson & Pyšek 2006). 

Lists focusing on the most relevant species have nonetheless already been compiled at the 

national level (Aboucaya, 1999) or for several French administrative regions (see the full list 

in Table 1). More recently, the DAISIE project has identified nearly 1,300 introduced and 

700 established plant species in France (Lambdon et al., 2008). These various lists define 

several categories of alien species: casual versus established species, major invasive species, 

potential invasive species or species only requiring monitoring (observation list), with 

sometimes finer subdivisions within these broad categories (Lacroix et al., 2007). As a 

consequence, the current criteria used to define invasiveness are far from homogeneous. This 

situation clearly shows the need to build a standardized approach, to be used as a basis for 

producing reference lists of non-native plants in order to highlight the species that need 

priority actions. 

Risk analysis as tools for preventive actions 

In Europe, plant protection services in line with the European and Mediterranean Plant 

Protection Organization (EPPO) activities, have historically used Pest Risk Analysis (PRA) 

to identify the probability of introduction, establishment and impact of pest species (insects, 

diseases) in a defined area, and if necessary, PRA defines what are the most appropriate 

measures of preventive control. Since 2002, EPPO has extended the use of the PRA scheme 

to study invasive plants (Schrader et al., 2010). However, regarding the number of potentially 

invasive species already present on the European continent (or absent but with a high 

probability of being introduced), it is not possible to perform a full PRA for all these species 

as the scheme is long and very detailed. For this reason, EPPO is currently developing a tool 

for quick and transparent prioritization (EPPO Prioritization Process for Invasive Alien 

Plants, abbreviated EPPO PP in the following text) in order to i) provide a clear overview of 

invasive and potentially invasive alien plants present in 50 European and Mediterranean 

countries in the EPPO region, ii) establish priorities among the species requiring a PRA. 

During the last 15 years, other risk assessment tools have been more specifically 

developed for invasive plants: 

- The Australian Weed Risk Assessment (Phelloung, 1995), one of the first and still the 

most acknowledged and used throughout the world (Gordon et al., 2008). The assessment of 

a species is probably shorter than with a PRA but still relatively long to be used as a quick 

assessment tool. 



121

Table 1 - Numbers of alien, established and invasive species reported in the recently 

published regional floristic atlases, regional floras or other available publications about 

invasive species in France. 

1 Established 

Regions Alien taxa 

taxa 

Invasive 

taxa 

Total 

number 

of taxa 2 

References 

Auvergne ~ 614 (24%) ~ 205 (8%) 

12 * (0.5%) 

56** (2%) 

2560 Antonnetti et al. (2006) 

Basse-Normandie 287 (18%) 

11* (0.7%) 

16** (1%) 

1620 

Provost (1993) ; Zambettakis & 

Magnanon (2008) 

Bourgogne - 125 (7%) 36 (2%) 1847 Bardet et al. (2008) 

Bretagne - - 

17* 

21** 

- Magnanon et al. (2007) 

- Côte-d‘Armor - - 

8* (0.7%) 

12** (1%) 

1150 Philippon et al. (2006) 

- Finistère 380 (34%) 

13* (1%) 

21** (2%) 

1129 Quéré et al. (2008) 

- Ille-et-Vilaine 200 (15%) 

9* (0.7%) 

16** (1%) 

1373 Diard (2005) 

- Morbihan 344 (20%) 191 (11%) 

9* (0.7%) 

18** (1%) 

1694 Rivière (2007) 

Centre - - - - 

- Loiret - 103 (9%) 

7* (0.5%) 

15** (1%) 

1382 Pujol et al. (2007) 

Corse 404 (17%) 153 (6%) 30 (1%) 2397 Jeanmonod & Gamisans (2007) 

Drôme 72 (3%) 74 (3%) 16 (0.7%) 2385 Garraud (2003) 

Franche-Comté - - 

38* 

49** 

- Ferrez (2006) 

Île-de-France - - - - 

- Essonne 23 (2%) 1215 Arnal & Guittet (2004) 

- Eure-et-Loir 129 (9%) 65 (5%) 

8* (0.6%) 

45** (3%) 

1366 Dupré et al. (2009) 

- 

Denis 

Seine-Saint- 

269 (25%) 127 (12%) 

10* (0.9%) 

12** (1%) 

1089 Filoche et al. (2006) 

Mediterranean 

area 

1253 351 60 - Brunel & Tison (2005) 

Pays de la Loire - - - - Lacroix et al. (2007) 

- Loire- 

Atlantique 

Vendée 

et 360 (19%) 204 (11%) - 1850 Dupont (2001) 

- Sarthe 364 (24%) 173 (11%) 

10* (0.7%) 

12** (0.8%) 

1525 Hunault & Moret (2009) 

- Mayenne 105 (7%) - 1441 David et al. (2009) 

1 

Alien species gathers all introduced species including established species, casual aliens and 

subspontaneous species, 

2 

the total number of taxa includes both introduced and native taxa 

*: invasive species, ** : potential invasive species, -: no data available. 

- In the United States, precise tools for assessing environmental impacts have been 

developed during the 2000s (Warner et al., 2003, Morse et al., 2004, Randall et al., 

2008). Conducting such an analysis however needs a lot of information about the 

impact on ecosystem processes or about recent population dynamic which are often 

not available for emergent species. 



122

- For Central Europe, Weber & Gut (2004) have developed a much shorter assessment 

(twelve questions). Andreu & Vila (2009) have tested it for Spain and found very 

similar results compared to the Australian WRA. 

In France, a specific risk assessment or an adaptation of an existing tool is still lacking. To 

date, the Plant Health Laboratory (LNPV) is involved in the development of the EPPO PP 

while the Federation of National Botanical Conservatories (FCBN) has tested the Weber & 

Gut risk assessment in order to update the list of species regulated by the Environmental 

Code (prohibition of sale and introduction into the wild). Currently this list only contains two 

species: Ludwigia grandiflora and Ludwigia peploides. Seventy-three species have been 

assessed and could potentially be added in the next years after negotiations with the different 

stakeholders. 

Aims of the study 

The first aim of this work was to use a first check-list of the most relevant alien plant 

species in France, in order to identify emergent invasive species which are priority species for 

several kinds of actions according to the threat they represent to natural and semi-natural 

ecosystems or to agricultural activities. At the national level, the present study is a part of a 

longer-term project which intends to i) inventory the comprehensive list of all nonindigenous 

plants recorded in France and ii) build a transparent and standardized protocol 

that can be used to decide which species of this list are invasive and which should be subject 

to management measures. With this end in mind, the present study has the objective to test 

and to compare the two methods of prioritisation already in use, i.e. the EPPO PP and the risk 

assessment of Weber & Gut (2004) for central Europe. Finally, at the European level, this 

study aims to validate the EPPO PP by applying it to a large list of alien species which has 

been, at least partially, previously classified by expert judgement (Aboucaya, 1999). 

Material & Methods 

Species assessed 

A plant data set gathering 370 species of various statuses was pre-selected to be tested 

through the 2 prioritization methods: 

- The initial list included 217 alien species present in France and identified by 

Aboucaya (1999) as major invasive species (61 taxa), as potential invasive species to 

monitor (65 taxa) or as presenting less risk (91 taxa part of an observation list). 

- this initial list has been updated with a data set containing 91 species reported in more 

recent check-lists published at the regional scale (see Table 1). 

- species acknowledged as invasive at the European scale by EPPO have been added : 

15 species out of the 21 of the EPPO Alert List, 2 out of the 9 species of the EPPO A2 

list (species of serious phytosanitary concern which are recommended for regulation 

by EPPO) and 1 out of the 38 species of the EPPO List of invasive alien plants. 

- species which are already invasive in neighbouring countries but not yet present in 

France were also added, based on the following published lists: 

o Italy : Celesti-Grapow et al. (2009), 

o Spain : Dana et al. (2004), 

o Belgium : Invasive Species in Belgium (2010), 

o Switzerland : Swiss Commission for Wild Plant Conservation CPS/SKEW 

(2006). 



123

Description of the risk assessment methods used 

All the 370 species were assessed using the EPPO Prioritization process (Brunel et al., 

2010) while 288 species for which sufficient information is available were also evaluated 

with the risk assessment developed by Weber & Gut (2004) for Central Europe (abbreviated 

W-G WRA in the remainder of the document). It contains twelve questions dealing with : the 

area of origin, range size in the risk area, invasiveness elsewhere, mode of reproduction and 

dispersal, plant height and life form, population size and type of habitat invaded. As the W-G 

WRA was developed for continental areas, question 11: ―Habitats of species. Allocate 

species to one of the following. If more than one statement applies, take the one with the 

highest score. Riparian habitats (3), Bogs/swamps (3), Wet grasslands (3), Dry 

(xeromorphic) grasslands (3), Closed forests (3), Lakes, lakeshores, and rivers (3), Other 

(0)” was adapted to the French conditions, adding ―Dunes and coastal cliffs‖ as a relevant 

habitat. For more details on the latter protocol, please refer to the corresponding publication. 

The EPPO PP consists in eleven questions including key aspects as invasiveness 

elsewhere in the world, climate match, spread capacity, impact on agriculture and 

environment. The first part of the process aims at classifying plants into several categories. 

According to the possible combination of scores for spread potential and adverse impact, 

three outcomes are possible (Figure 1). 

Adverse impacts 

Spread potential 

Low Medium High 

Low 

Minor 

concern 

Minor 

concern 

Observation 

list 

Medium Minor 

concern 

Observation 

list 

Observation 

list 

High 

Observation 

list 

List of 

(potential) 

invasive plants 

List of (potential) 

invasive plants 

Figure 1 - Matrix of spread potential and adverse impacts of assessed species with the 

corresponding outputs. 

If the species qualifies as an invasive alien plant of major concern through this first set of 

questions, the second section of the process then investigates the efficiency of international 

measures (to be justified through a pest risk analysis) to prevent the entry and spread of the 

species and whether the species still has a significant suitable area for further spread (in order 

to exclude species which are already too widespread and can no more be controlled at low 

cost). 

For the most important questions (climate matching, spread potential and impacts), a level 

of uncertainties is defined. This relativizes the risk and identifies points where research 

efforts must be driven. 

 

In the latest version of the EPPO PP (Brunel et al., 2010), species with medium spread and high impact are on 

the observation list, in order to select only the most invasive species. 

124 



Source of data 

The necessary information for the species were obtained from various sources. The status 

of the species in France (only cultivated, casual, established) was obtained from Kerguélen 

(1993) updated by Bock (2005) and from various recent floristic atlases (Table 1). 

Geographical distribution data for Europe was obtained from the DAISIE website. I only 

considered the number of countries where the species are clearly established (excluding 

casual and unknown occurrences). Native areas of alien species were checked with the online 

database from the Germplasm Resources Information Network (GRIN), National Germplasm 

Resources Laboratory, Beltsville, Maryland (http:// www.ars-grin.gov/npgs/tax/index.html), 

as well as from recent standard European floras (e.g. Flora Iberica, Flora d‘Italia, Flora 

Helvetica, Nouvelle Flore de Belgique, etc.). 

Climatic match was determined by considering the origin of the species, its current 

distribution and the World Map of the Köppen-Geiger climate classification (Kottek et al., 

2006). The potential area for further spread was determined according to current distribution 

in France or elsewhere in the world and the extent of the remaining suitable climates and 

habitats in the area under consideration. 

Status of the species as a weed elsewhere was taken from the Global Compendium of Weeds 

(GCW) (Randall, 2007). As the GCW probably exacerbates invasiveness, the author decided 

that to be considered as invasive elsewhere, a species has to combine at least three of the 

following qualifiers: ―agricultural weed‖, ―environmental weed‖, ―noxious weed‖, ―sleeper 

weed‖ and ―weed‖. 

Species traits (life form, seed number and viability, vegetative reproduction, dispersal 

mode) were extracted from various publications (species fact sheets, previous weed risk 

assessments in other countries). Data on habitats and the ecology of the species and local 

abundance were taken from recent regional floristic atlases (Table 1) and other botanical 

publications. Frequency and impact in cultivated fields was taken from Jauzein (1995) and 

Mamarot (2002) while herbicide resistance was checked with Heap (2010). 

Concerning the population density in natural and semi-natural habitats as well as the 

impact in agricultural lands, if the species under assessment is not present in France, I used 

data within the European range or within another area where the species has been introduced 

with a similar climate to France. The uncertainty associated to these questions was ranked as 

medium if data was taken from another European country, or as high if data was taken from a 

country with similar climate elsewhere in the world. This also introduces a distinction 

between invasive species (with observed impacts in France) and potential invasive species 

(not yet present in France but already invasive under similar ecological conditions). 

Results & Discussion 

Global results 

The list of invasive species resulting from the EPPO Prioritization Process and the scores 

from the W-G WRA are given in Appendix. Out of the 370 species assessed with the EPPO 

Prioritization Process, 127 were classified as invasive or potentially invasive species, of 

which 32 were identified as priorities for PRA, 232 species were of minor concern and placed 

on the observation list and 8 species were not considered as invasive or potentially invasive. 



125

The scores of the 288 species assessed by the W-G WRA ranged from 12 to 38, with 95 

species presenting a high risk, 147 species presenting an intermediate risk (further 

observation needed) and 30 species having only a low risk. 

Comparison of the two methods of prioritization 

Comparing the previous classification of alien species based on expert judgments 

(Aboucaya, 1999), a substantial agreement with EPPO Prioritization Process (Cohen‘s Kappa 

= 0.75) and the Weber & Gut Protocol (Cohen‘s Kappa = 0.73) was found. Table 2 shows 

that the agreement between the EPPO Prioritization Process and the Weber & Gut Protocol is 

also good (Cohen‘s Kappa = 0.75). For example, among the 32 species which are priority for 

a PRA according to EPPO PP, 24 have also a high risk and 8 an intermediate risk according 

to the W-G WRA. 

Table 2 - Comparison of the classification of the 280 alien species as either invasive or not 

by the EPPO Prioritization Process and by the Weber & Gut Risk assessment. 

Weber & Gut WRA 

EPPO PP Lists High Risk Intermediate risk Low Risk Total 

Priority for a PRA 24 8 32 

Invasive Species 59 32 91 

Observation List 18 107 24 149 

Not Invasive 3 5 8 

Total 101 150 29 280 

The differences between the two methods can be explained in two ways. Most of the 40 

species that were only identified as invasive by the EPPO PP (Table 2), are agricultural 

weeds with economical impact on crop production (e.g., Abutilon theophrasti, Bidens 

subalternans, Conyza spp., Panicum spp., Xanthium spp.). The W-G WRA (and the previous 

national and regional check-lists, Table 1) only aims at identifying species at risk for 

biodiversity: the scores of agricultural weeds are therefore low because they are mostly 

annuals and species restricted to man-made habitats (on average, these traits lead to - 5 

points). This is also true for small annual species whose impacts are probably less than 

perennial or woody invasives but can nevertheless be reported as forming dense 

monospecific stands threatening native vegetation like Eragrostis pectinacea in sandy areas 

of the Loire valley (Dupont, 2001) or Claytonia perfoliata in coastal sand dunes (Quéré et al., 

2008). 

On the other hand, the 18 species that were only identified as invasive by the W-G WRA 

are species that do not yet have an invasive behaviour in France. If a species is already 

present in France, the EPPO PP mainly relies on its effective impact in natural or seminatural 

habitats and pays less attention to its behaviour elsewhere. For example Eupatorium 

adenophorum is established in riparian habitats in Corsica without forming dense populations 

(Jeanmonod & Gamisans, 2007). According to the intrinsic biological traits of this species 

(vegetative reproduction, life form, plant height and seed dispersal), the W-G WRA has 

identified it as presenting a high risk, which is consistent with the invasive behaviour of this 

plant in Spain (however, if the EPPO PP was applied at the EPPO region scale, it would also 

have ranked this species as invasive). This illustrates the greater predictive power of the W-G 

WRA more suitable for species that are not yet present. So, the W-G WRA appears as a good 

complement to the EPPO PP, particularly in order to identify future potential weeds. 



126

The observation list obtained through the EPPO PP 

The observation list contains 232 species. The mean score of the species on the 

observation list with the W-G WRA was 24.2 but it ranged from 12 to 32, with 18 species 

recognised as being potentially invasive (score>28), meaning that some species have intrinsic 

traits that confer them the ability to spread and invade. Lag phase can sometimes last several 

decades before an introduced species suddenly occupies a wider range of habitats and/or 

become invasive (Kowarik, 1995). 

Two broad groups of species can be distinguished: those which are confined to ruderal and 

man-made habitats environments (epoecophytes) and those that are already established in 

natural or semi-natural habitats (hemi- and holo-agriophytes). The first group contains a 

significant proportion of annuals typically found in disturbed areas: Bidens bipinnata, 

Eleusine indica, Eragrostis mexicana, Euphorbia maculata, Veronica persica. They are of 

minor concern as they are well controlled in cultivated crops. For some species considered as 

invasive in previous lists, like Nicotiana glauca (Jeanmonod & Gamisans, 2007) or Araujia 

sericifera (Brunel & Tison, 2006), there are some uncertainties: they are forming dense 

stands but the naturalness of the invaded habitats is not certain. I have taken the decision to 

downgrade such species to the observation list, paying closer attention to the nature of the 

invaded habitats. Special attention must also be given to Conyza floribunda, which is 

reported as a ruderal species over most of the territory but seems able to penetrate into natural 

habitats in areas where it is currently expanding, e.g., in Normandy (Zambetakkis & 

Magnanon, 2008) and in the Côtes-d'Armor (Philippon et al., 2006). 

The second group gathers species that have already crossed the environmental barriers. 

Among these species, some have been eliminated because of their low dispersal ability, due 

for example to few or no production of viable seeds, coupled with a lack of long-distance 

dispersal mechanisms (Elaeagnus x submacrophylla, Spiraea spp.). Other species have not 

(yet) been observed to form dense monospecific populations: Amelanchier spicata, 

established in oak forests on acid soils in Burgundy (Bardet et al., 2008), Arctotheca 

calendula, Aptenia cordifolia or Tetragonia tetragonoides, which are established in coastal 

sand dunes. Finally some species are considered as well integrated in their new habitat, e.g., 

Juncus tenuis or Eleocharis bonariensis (Dupont, 2001). 

Some of the 18 species on the observation list that should be put under particular 

surveillance are highlighted here as they are already serious plant invaders in neighbouring 

countries and as their score with the W-G WRA was superior to 27, meaning that they 

present a high risk: 

Ageratina adenophora (Spreng.) King & H. Rob. [syn: Eupatorium adenophorum 

Spreng.] (WG-WRA Score: 32): established along rivers in Corsica (Jeanmonod & 

Gamisans, 2007) and in the Alpes-Maritimes department (Carles & Thébaut, 2010). In the 

South of Spain and in the Canary Islands, this species is spreading and forms dense stands 

along rivers and in riverine forests (Dana et al., 2004). It has a prolific asexual seed 

production (apomixis) which can reach 60 000 seeds/m² (Weber, 2003). 

Asclepias syriaca L. (WG-WRA Score: 34), established since at least the mid 19 th century 

(Garraud, 2003) in the Center and the South of France. Most of the time the species is only 

reported as escaped from gardens where it is cultivated. In the South of the Rhone Valley, it 

can however exhibit an invasive behaviour in riparian habitats, without forming populations 

exceeding 80% coverage, the stands can however reach high densities. 



127

Hakea sericea Schrad. & J.C.Wendl. (WG-WRA Score: 30), established in the Esterel 

mountains both in the Var and the Alpes-Maritimes departments. It is invasive in Portugal, 

mainly in disturbed habitats (roadsides) but also in undisturbed shrublands. It is cold, drought 

and wind resistant. It is adapted to fires which lead to mass release of seeds and stimulates 

germination. This is why Hakea sericea could rapidly become dominant in the Pine forests of 

the Esterel mountains which are prone to regular fires during summer. 

Delairea odorata Lem. [syn.: Senecio mikanioides Otto ex Walp.] (WG-WRA Score: 29). 

It is cultivated and sometimes escapes from gardens in Bretagne, locally in the Finistère 

department, it can form dense stands several meters high, smothering trees and shrubs (Quéré 

et al., 2008). It is also established on the coastal areas of Provence. The plant spreads by 

vegetative growth, the stolons fragment easily and can quickly produce new plants. 

Mahonia aquifolium (Pursh) Nutt. (WG-WRA Score: 29) is considered invasive in dunes, 

rock outcrops, grasslands and woodlands in Belgium where its clonal growth could lead to 

dense populations that are likely to overgrow and outcompete native species and accelerate 

the colonisation of open habitats by woody vegetation. In France, this species is largely 

cultivated and well established in different kind of habitats: dunes in the North of France 

(Toussaint et al., 2008), hedges and cool temperate forests in Burgundy (Bardet et al., 2008), 

edges of grasslands (Antonnetti et al., 2006); however no dense stands have been yet reported 

in these habitats. 

The List of Invasive Species obtained through the EPPO PP 

One hundred and twenty seven (127) species have been identified as invasive or potential 

invasive species by the EPPO PP. This list can be subdivided according to the extent of the 

invaded territory and according to the type of impact (environmental or economical). 

Forty widespread invaders are already widely dispersed in all or several biogeographical 

regions of France (e.g., Reynoutria japonica, Acer nedundo, Senecio inaequidens) while 77 

regional invasive species that are still restricted to only one biogeographical region, in either 

atlantic (Polygonum polystachyum, Rhododendron ponticum, Spartina alternifolia), 

continental (Cotoneaster horizontalis, Rudbeckia laciniata) or Mediterranean climates 

(Acacia dealbata, Lonicera japonica). 

Ninety-six species are environmental weeds exhibiting, at least in one locality, large, 

dense and persistent populations in natural or semi-natural habitats with can have a cover at 

least 80 %. 30 species represent a major concern for agricultural activities (6 species are both 

agricultural and environmental weeds: Artemisia verlotiorum, Galega officinalis, Lindernia 

dubia, Phyla filiformis, Phytolacca americana and Sicyos angulatus). 

The mean score with the W-G WRA was 29.8, ranging from 21 to 38. The species with 

the highest score was Solidago gigantea (38) which combines high dispersal capacity, 

efficient vegetative reproduction and dense stands in wet meadows. Other environmental 

weeds with high scores include some aquatic invasive species that fragment easily and can 

rapidly cover entire water bodies: Azolla filiculoides Lam. (34), Elodea nuttalii (Planch.) 

H.St.John (34), Ludwigia grandiflora (Michx.) Greuter & Burdet (33), Ludwigia peploides 

(Kunth) P.H.Raven (36) and Myriophyllum aquaticum (Vell.) Verdc (34). Some trees like 

Acacia dealbata (36), Prunus serotina (35), Ailanthus altissima (33) or Acer negundo (32) 

also achieve high scores. 



128

Table 3 - List of invasive and potential invasive plants with high priorities for a PRA in 

France ranked according to their score with the W-G WRA. 

Species Origin 2 Area 3 Habitat I 4 Score 

Hydrocotyle ranunculoides L.f. Am. [M]AC Static or slow-flowing freshwater bodies E 34 

Rosa rugosa Thunb. E. As. A Coastal dunes and sandy shores E 33 

Senecio angulatus L.f. S. Afr. M Coastal shrublands, roadsides, wastelands E 32 

Acacia saligna (Labill.) H.L.Wendl. Aust. M Heathlands, coastal scrub and beaches, forests E 31 

Crassula helmsii (Kirk) Cockayne Aust. A[C?] 

Static or slow-flowing freshwater bodies, edges 

E 

of ponds, lakes. 

31 

Gomphocarpus fruticosus (L.) R.Br. Afr., Arab. M Wastelands, roadsides, torrents of river [E] 31 

Eichhornia crassipes (Mart.) Solms S.Am. MA Static or slow-flowing freshwater bodies [E] 30 

Elide asparagoides (L.) KerguŢlen S. & E. Afr. M 

Roadsides, wastelands, riversides, edges of 

E 

scrublands 

30 

Pistia stratioides L. S. Am. MA Static or slow-flowing freshwater bodies E 30 

Sesbania punicea Benth. S. Am. M Riparian habitats, wetlands, ruderal habitats E 30 

Acacia longifolia (Andrews) Willd. Aust. M 

Riparian habitats, woodlands, 

coastal dunes and scrub 

grasslands, 

E 29 

Alternanthera philoxeroides (Mart.) 

S. Am. 

Griseb. 

[M]A Rivers, lakes, ponds, and irrigation canals [EA] 29 

Cyperus esculentus 

leptostachyus Böck. 

var. 

1 

Am. AC Maize fields, riparian habitats AE 29 

Humulus japonicus Siebold & Zucc. E. As. M[AC] Riverbeds, alluvial deposits rich in nutrients E[A] 29 

Periploca graeca L. E. Med. M 

Riparian habitats, Populus alba forests, sand 

E 

dunes 

29 

Salpichroa origanifolia (Lam.) Baill. S. Am. MA Coastal dunes, ruderal habitats E 29 

Senecio deltoideus Less. S. Afr. M Wet areas E 29 

Sicyos angulatus L. N. Am. MA Maize fields, riparian habitats AE 29 

Solanum elaeagnifolium Cav. Am. M Wastelands [potentially in all cultivated fields] [A] 28 

Acacia retinodes Schltr. Aust. M 

Mediterranean woods, ruderal habitats, coastal 

E 

sands 

27 

Cabomba caroliniana A.Gray Am. [M]AC Static or slow-flowing freshwater bodies E 27 

Phyla filiformis (Schreider) Meikle S. Am. M Damp meadows, edges of ponds E 26 

Akebia quinata Decne. T. As. [M]A Riparian habitats [E] 25 

Setaria faberi F.Herm. T. As. [M]A[C] Roadsides, highways, potentially maize fields [A] 25 

Hypericum majus (A. Gray) Britton N. Am. C Wetlands, edges of ponds E 23 

Alert List (species not yet established in France) 

Salvinia molesta D.S. Mitch. S. Am. [MA] Static or slow-flowing freshwater bodies [E] 33 

Pueraria lobata (Willd.) Ohwi As. [M] Riparian habitats, forest edges, woodlands [E] 32 

Spartina densiflora Brongn. S. Am. [A] Estuaries, interdital marine habitats [E] 30 

Myriophyllum heterophyllum Michx. N. Am. [MAC] Static or slow-flowing freshwater bodies [E] 29 

Apios americana Medik. N. Am. [MAC] Riparian habitats, maize fields [AE] 28 

Echinocystis lobata (Michx.) Torr. & 

N. Am. [C] Forest fringes, riparian habitats in floodplains [E] 26 

A.Gray 

Eriochloa villosa (Thunb.) Kunth E. As. [C] Maize fields, hedgerows, riversides [A] 24 

1 

Cyperus esculentus var. esculentus is native at least in the mediterranean part of France. The variety 

leptostachyus Boeck is native from America and naturalized in the South-West; the variety sativus Boeck is 

naturalized around horticultural farms. 

2 

Abbreviations used for area of origin : Afr.=Africa, Am.=America, Arab.=Arabic Peninsula, As.=Asia, 

Aust.=Australia, E.=East, N.=North, S.=South, W.=West, Med.=Mediterranean, 

3 

Three main biogeographical areas have been distinguished : M. for Mediterranean, A. for Atlantic (oceanic) 

and C. for continental. Letters between brackets means that the species is not (yet) recorded in the 

corresponding area but this area is however at risk. 

4 

Impact of the species: A.=Agricultural impact, E.=Environmental impact. Letters between brackets mean that 

the species has not yet had an impact. 



129

One original component of the EPPO PP is to take into account species which threaten 

agricultural activities. Most alien weeds are just considered as one more weed, without 

particular difficulties in managing them in a context of intensive practices based on the use of 

herbicide. Agricultural weeds included in the present list of Invasive species are those that are 

reported to form dense stands within fields despite a classical weed control program. These 

species generally require specific measures due to a lack of control of the available herbicides 

and/or due to other weedy traits like an effective vegetative reproduction. Most of these 

species occur in maize fields (Amaranthus spp., Panicum spp., Sicyos angulatus) or in 

Mediterranean vineyards (Bidens subalternans, Conyza spp.). Some species are of concern in 

pastures due to their toxicity for cattle (Galega officinalis) or because they are not grazed and 

thus decrease the quality of forage (Phyla filiformis). 

Invasive Species requiring a PRA 

Among the list of Invasive species, 25 species that still have a limited distribution 

compatible with a possible eradication or containment at low cost were identified. Seven 

species not yet established in France but invasive in neighbouring countries were also 

identified as potentially invasive in France. These 32 species have therefore the highest 

priority for a national PRA in France. Table 3 shows that aquatic and riparian habitats as well 

as the Mediterranean area are the most threatened. 

Aquatic species 

Wet biotopes are considered as more vulnerable to invasions than dry biotopes. Two third 

of the species with high priority (Table 3) are affecting riparian habitats, damp meadows or 

aquatic habitats. PRAs at the EPPO scale have already been performed for three out of the six 

species invading static or slow-flowing water bodies: Crassula helmsii, Eichhornia crassipes 

and Hydrocotyle ranunculoides. All three species are now on the EPPO A2 List (regulation 

as quarantine pests is recommended). Crassula helmsii invades edges of ponds in less than 20 

locations in Bretagne and Normandie. Eradication is still possible and is under development 

at least in Finistère (Quéré et al., 2008). Eichhornia crassipes and Pistia stratioides are only 

casual aliens in France. Episodic blooms of Pistia stratioides have already been recorded in 

the South-West (Jalle de Blanquefort) during the 2003 summer (Dutartre, pers., comm., 

2010). In the South and the South-West of France, Eichhornia crassipes has no stable 

populations. The monitoring of habitats at risk should continue for these two species. In 

Corsica, an invasive stand of E. crassipes had been detected in lagoon basins, near the Figari 

airport, and is currently under eradication (Jeanmonod & Schlüssel, 2008). Cabomba 

caroliniana A.Gray. was first observed in France in 2005 invading 15 km along the 

Burgundy canal near Dijon (Dutartre et al., 2006). More recently, it was also recorded in two 

locations in the « Canal du Midi » near Toulouse (Enjalbal, 2009). However, the EPPO PRA 

does not conclude that there is a clear risk. Alternanthera philoxeroides (Mart.) Griseb. is 

localized along the Garonne and Tarn rivers in the South-West without yet exhibiting an 

invasive behaviour (Georges, 2004). It should be closely monitored because it has recently 

been observed spreading on the Arno River in Italy (Brunel et al., 2010). 

Mediterranean region 

The impact of Acacia dealbata is well known (even if this species is still widely sold and 

planted in areas at risk). Some other Acacia sp. (A. longifolia, A. retinodes, A. saligna) are 

still of limited distribution in the Var department and in Corsica. According to their impact in 

other Mediterranean areas (e.g. Portugal), Acacia sp. should be eradicated where and when 

possible and should be used anymore in plantations. Several Senecio sp. also represent a risk, 



130

particularly Senecio angulatus which already forms dense stands in coastal scrublands or in 

wet habitats. 

Alert List 

An awareness campaign could be implemented in order to prevent the introduction of 

species not yet established in France. Among species used in aquaria, Myriophyllum 

heterophyllum and Salvinia molesta should be prohibited or at least, a warning label should 

alert people not to discard these species in natural areas. Both species can invade static or 

slow flowing waters and can rapidly reach high coverage. Salvinia molesta is a free floating 

perennial fern, probably of hybrid origin. It is sterile and spreads by vegetative growth and 

fragmentation. It is one of the most invasive aquatic plants in tropical and southern Africa, in 

tropical Asia and Australasia (Weber, 2003). In Europe, it is already invasive in Italy: it has 

covered the entire water surface (around 1.7 ha) of a lake in less than three months (Giardini, 

2004). Myriophyllum heterophyllum has been recorded in Germany and Austria and has 

shown invasive behaviour where it has been introduced in western North America 

(Washington State Noxious Weed Control Board Website, 2010). 

Several species used as ornamentals should also be subject to preventive measures (these 

species should no longer be available for purchase in garden centers or nurseries, or at least 

advices on their proper use and disposal should be provided). This is the case for two vine 

species not yet established in natural areas in France: Echinocystis lobata and Pueraria 

lobata. Echinocystis lobata is an annual fast-growing species, covering large areas in 

floodplains, riparian habitats and forest fringes in a large part of Central Europe (Germany, 

Poland). Its spatial occupation competes with native species (Klotz, 2007). Pueraria lobata is 

a perennial native from eastern Asia. It is invasive in Italy and in the south of Switzerland. It 

has negative effects on crop production, forestry production and the natural environment, as it 

smothers existing flora. The severity of its impact has justified its addition to the EPPO A2 

List in 2006. 

Several Spartina sp. are already serious invaders in estuaries all along the French Atlantic 

coast. Another species, Spartina densiflora is invasive in Portugal and Spain but is not yet 

recorded in France. As for other invasive Spartina, invasions by S. densiflora may deeply 

change the structure of foreshores previously occupied by annuals Salicornia sp. These dense 

clones may also slow the flow of water, and thus increase the rate of sedimentation. 

Introduction of contaminated seeds is harder to prevent. Maize fields are the most at risk 

for the establishment of new alien weeds due to several favourable conditions (empty 

ecological niche for summer annuals, irrigation, Etc.). Therefore, the national arable weed 

monitoring implemented in France (Biovigilance Flore network, see Fried et al., 2007) 

should particularly look after Apios americana, already invasive in Italy and Eriochloa 

villosa, invasive in North America and spreading rapidly in Central Europe. 

Conclusions & Perspectives 

The first aim of this work was to identify priority species to perform national PRAs on and 

to raise awareness on those species that can still be subject to early detections and preventive 

eradications. As a secondary outcome, this study provided an observation list and a list of 

invasive species which are both ranked according to spread potential and effective impact 



131

eported in France. Such lists can have many possible uses. I propose some examples here 

and the LNPV strongly encourages their development. 

Actions to develop on the ranked lists of invasive species 

Prioritized lists of invasive species can provide information for the development of 

appropriate regulations and voluntary restrictions on intentional plantings. To date, only two 

species are regulated in France: the sale, purchase, use and introduction into the wild of 

Ludwigia grandiflora and Ludwigia peploides is forbidden by the Order of May 2, 2007 

(Articles L. 411-3 and R. 411-1 to R. 411-5 of the Environmental Code). Many other invasive 

species have the same level of impact and should also be added to the list of regulated 

species. With this end in mind, the French national botanical conservatories have used the W- 

G WRA to assess and to rank a list of 73 species (unpubl. doc.). Nurseries and garden centers 

that want to develop environmental-friendly actions can use this list to remove invasive 

plants from their catalogues (for more details, see the EPPO Code of conduct on horticulture 

and invasive alien plants). 

Unlike other countries such as Belgium or Switzerland, France has no Black List of 

invasive species. Even if such a list has no regulatory or legal value, it can have an 

authoritative value and provide useful information for people in nearby countries or in more 

distant areas with similar climates who want to identify species with a high likelihood of 

spread and impacts. Thus, prioritized lists of alien species can be a useful tool to exchange 

information with other countries in the framework of an early detection system at the 

European scale. 

Land managers facing numerous invasive species in nature reserves can also use such 

categorized lists to determine priorities for control programs. Last but not least, this work 

also highlights species for which further research is needed to determine their spread capacity 

and the exact nature of their impact. 

Toward an invasive plant risk assessment council 

This list is still a working document that will need to be validated by a committee 

gathering other partners such as, regional experts from national botanical conservatories and 

scientists working on plant invasion in France. Moreover, it is important to note that 

prioritisation of alien plants is not a static process. When new information becomes available, 

species will be re-evaluated especially if new data could influence the ranking of the species. 

This invasive plant risk assessment committee that could be established, could also validate a 

specific risk assessment method for identifying invasive species in France and oversee the 

future work on the inventory of non-native plants in France. 

References 

Aboucaya A (1999) Premier bilan d‘une enquête nationale destinée à identifier les xénophytes invasifs sur le 

territoire métropolitain français (Corse comprise), in Les Actes du colloque « Les plantes menacées de 

France », Brest, 15-17 octobre 1997. Numéro special de la Société Botanique du Centre-Ouest 19, 463- 

482. 

Andreu J, Vilà M (2009) Risk analysis of potential invasive plants in Spain. Journal for Nature Conservation 

18, 34-44 

Antonetti P, Brugel E, Kessler F, Barbe JP & Tort M (2006) Atlas De La Flore D'Auvergne. Conservatoire 

botanique national du Massif central, Chavaniac-Lafayette (FR). 

Arnal G, Guittet J (2004) Atlas de la flore sauvage du département de l‘Essonne. Biotope, Mèze (Collection 

Parthénope) ; Muséeum national d‘Histoire naturelle, Paris (FR). 



132

Bardet O, Féderoff E, Causse G, & Moret J (2008) Atlas de la flore sauvage de Bourgogne Biotope, Mèze (Coll. 

Parthénope) ; Muséum national d'Histoire naturelle, Paris (FR). 

Bock B (2005) Base de Données Nomenclatural de la Flore de France v4.02: http://www.telabotanica.org/page:eflore 

[Accessed on March 2010] 

Brunel S & Tison JM (2005) A method of selection and hierarchization of the invasive and potentially invasive 

plants in continental Mediterranean France. In: Invasive Plants in Mediterranean Type Regions of the 

World. Proceedings of the International Workshop, 25–27 May 2005 (Ed. Brunel S). pp. 27–36. Council 

of Europe Publishing, Mèze, France. 

Brunel S, Schrader G, Brundu G, Fried G (2010) Emerging invasive alien plants for the Mediterranean Basin 

EPPO Bulletin 40, 219-238. 

Cadotte MW, Murray BR, Lovett-Doust L (2006). Ecological patterns and biological invasions: Using regional 

species inventories in macroecology. Biological Invasions 8, 809–821. 

Carles L & Thébault L (2010) Guide de la flore des Alpes-Maritimes du Mercantour à la Méditerranée, 

Editions Gilleta Nice Matin, Nice (FR). 

Celesti-Grapow L, Alessandrini A, Arrigoni PV, Banfi E, Bernardo L, Bovio M, Brundu G, Cagiotti MR, 

Camarda I, Carli E, Conti F, Fascetti S, Galasso G, Gubellini L, La Valva V, Lucchese F, Marchiori S, 

Mazzola P, Peccenini S, Poldini L, Pretto F, Prosser F, Siniscalco C, Villani M, Viegi L, Wilhalm T & 

Blasi C (2009) Inventory of the non-native flora of Italy. Plant Biosystems 143, 386–430. 

DAISIE European Invasive Alien Species Gateway: http://www.europe-aliens.org [Accessed on May 2010] 

Dana ED, Sobrino E, & Sanz-Elorza M (2004) Plantas invasoras en España: un nuevo problema en las 

estrategias de conservación. In: Atlas y Libro Rojo de la flora vascular amenazada. (ed. Aeal Banares 

Baudet), pp. 1010-1029. Madrid (SP). 

David C, Gérard M, Hubert H, Jarri B, de Labarre Y, Ravet M (2009) Atlas de la flore de la Mayenne. Editions 

Siloë, Nantes (FR). 

Diard L (2005) Atlas de la flore de l’Ille-et-Vilaine. Editions Siloë, Nantes (FR) 

Dupont P (2001) Atlas floristique de la Loire-Atlantique et de la Vendée. Etat et avenir d‘un patrimoine. Tome 2 

Cartes et commentaires, Editions Siloë, Nantes (FR). 

Dupré R, Boudier P, Delahaye P, Joly M, Cordier J & Moret J (2009) Atlas de la flore sauvage du département 

de l’Eure-et-Loir. Biotope, Mèze (Collection Parthénope) ; Muséeum national d‘Histoire naturelle, Paris 

(FR). 

Dutartre A, Chauvin C, Grange J (2006) Colonisation végétale du canal de Bourgogne à Dijon. Bilan 2006 – 

Prospection de gestion. Voies Navigables de France, Cemagref. 87pp. 

Ferrez Y (2006) Définition d‘une stratégie de lutte contre les espèces invasives de Franche-Comté - Proposition 

d‘une liste hiérarchisée. Conservatoire Botanique de Franche-Comté, DIREN Franche-Comté, Union 

Européenne, 71 pp. 

Filoche S, Arnal G, Moret J (2006) La biodiversité du département de la Seine-Saint-Denis. Atlas de la flore 

sauvage. Biotope, Mèze (Collection Parthénope) ; Muséeum national d‘Histoire naturelle, Paris (FR). 

Fried G, Reboud X, Gasquez J, & Delos M (2007) 'Biovigilance Flore', a Long-Term French Weed Survey. 

20eme Conference du COLUMA.Journees Internationales sur la Lutte contre les Mauvaises Herbes, 

Dijon, France, 11-12 decembre, 2007. 

Garraud L (2003) Flore De La Drôme. Atlas Écologique Et Floristique CBN alpin de Gap-Charance, Gap (FR). 

Genovesi P & Shine C (2002) European Strategy on Invasive Alien Species. Convention on the Conservation of 

European wildlife and natural habitats. T-PVS (2003) 7 revised. 50 p. 

http://www.coe.int/t/e/Cultural_Cooperation/Environment/Nature_and_biological_diversity/Nature_prote 

ction/sc23_tpvs07erev.pdf?L=E [Accessed on March 2010]. 

Georges N (2004) L'Herbe à Alligator (Alternanthera Philoxeroides (Martius) Grisebach) atteint le département 

du Tarn-Et-Garonne. Le Monde des Plantes 484, 1-3. 

Giardini M (2004) Salvinia molesta D.S. Mitchell (Salviniaceae): the second record for Italy (Latium) and 

consideration about the control of this invasive species. Webbia 59. 

Gordon DR, Onderdonk DA, Fox AM & Stocker RK (2008) Consistent accuracy of the Australian weed risk 

assessment system across varied geographies. Diversity and Distributions 14, 234–242. 

Heap I (2010) The International Survey of Herbicide Resistant Weeds. Online Internet: 

www.weedscience.com [Accessed on May 2010]. 

Hunault G, Moret J (2009) Atlas de la flore sauvage du département de la Sarthe. Biotope, Mèze (Collection 

Parthénope) ; Muséeum national d‘Histoire naturelle, Paris (FR). 

Invasive Species in Belgium (2010): http://ias.biodiversity.be/species/all [Accessed on March 2010] 

Jauzein P (1995) Flore Des Champs Cultivés Sopra-INRA, Paris (FR). 

Jeanmonod D & Gamisans J (2007) Flora Corsica. Edisud, Aix-en-Provence (FR). 

Jeanmonod D & Schlussel A (2008) Notes and Contributions on Corsican Flora, XXII. Candollea 63, 131-151. 



133

Kerguélen M (1993) Index synonymique de la flore de France. Museum national d'histoire naturelle, Paris (FR). 

Klotz S (2007) Echinocystis lobata: http://www.europe-aliens.org/pdf/Echinocystis_lobata.pdf [Accessed on 

March 2010]. 

Kottek M, Grieser J, Beck C, Rudolf B & Rubel F (2006) World Map of the Köppen-Geiger climate 

classification updated. Meteorologische Zeitschrift 15, 259-263. DOI: 10.1127/0941-2948/2006/0130. 

Kowarik I (1995) Time lags in biological invasions with regard to the success and failure of alien species. In: 

Pysek, P. et al. (eds), Plant invasions, general aspects and special problems. SPB Academic Publishers, 

pp. 15-38. 

Lacroix P, Magnanon S, Geslin J, Hardegen M, Le Bail J & Zambettakis C (2007) Les plantes invasives des 

régions Basse-Normandie, Bretagne et Pays de la Loire 1. Définitions et clé pour l’élaboration de listes 

de plantes « invasives avérées », « potentiellement invasives », ou « à surveiller » Version 1. 

Conservatoire Botanique National de Brest, Brest (FR). 

Lambdon PW, Pysek P, Basnou C, Arianoutsou M, Essl F, Hejda F, Jarosik V, Pergl J, Winter M, Anastasiu P, 

Andriopoulos P, Bazos I, Brundu G, Celesti-Grapow L, Chassot P, Delipetrou P, Josefsson M, Kark S, 

Klotz S, KokkorisY, Kühn I, Marchante H, Perglova I, Pino J, Vilà M, Zikos A, Roy D & Hulme PE 

(2008) Alien flora of Europe: species diversity, temporal trends, geographical patterns and research 

needs. Preslia 80, 101–149. 

Magnanon S, Haury J, Diard L, Pelloté F (2007) Liste des plantes introduites envahissantes (plantes invasives) 

de Bretagne. Conseil scientifique régional du patrimoine naturel de Bretagne, 24 pp. 

Mamarot J (2002) Mauvaises Herbes Des Cultures ACTA Editions, Paris (FR). 

Morse LE, Randall JM, Benton N, Hiebert R & Lu S (2004) An Invasive Species Assessment Protocol: 

Evaluating Non-Native Plants for Their Impact on Biodiversity. Version 1. NatureServe, Arlington, VI. 

Muller S (2004) Plantes invasives en France. Muséum national d‘Histoire naturelle. Paris (FR), 168pp. 

(Patrimoines naturels, 62). 

Phelloung P (1995) Determining the weed potential of new plant introductions to Australia Report. Australian 

Weeds Committee and the Plant industries Committee, Perth (AU). 

Philippon D, Prelli R & Poux L (2006) La Flore Des Côtes-d'Armor Editions Siloë, Nantes (FR). 

Provost M (1993) Atlas de la répartition des plantes vasculaires de Basse-Normandie. Presses Universitaires de 

Caen, Caen (FR) 

Pujol D, Cordier J, Moret J (2007) Atlas de la flore sauvage du département du Loiret. Biotope, Mèze 

(Collection Parthénope) ; Muséeum national d‘Histoire naturelle, Paris (FR). 

Quéré E, Magnanon S, Ragot R, Gager L & Hardy F (2008) Atlas De La Flore Du Finistère Editions Siloë, 

Nantes (FR). 

Randall JM, Morse LE, Benton N, Hiebert R, Lu S & Killeffer T (2008) The Invasive Species Assessment 

Protocol: A Tool for Creating Regional and National Lists of Invasive Nonnative Plants that Negatively 

Impact Biodiversity. Invasive Plant Science and Management 1, 36–49. 

Randall RP (2007) Global Compendium of Weed: http://www.hear.org/gcw/ . [Assessed on May 2010] 

Richardson DM, Pyšek P (2006) Plant invasions: Merging the concepts of species invasiveness and community 

invisibility. Progress in Physical Geography 30, 409–431. 

Rivière G (2007) Atlas de la Flore du Morbihan Siloë Editions, Nantes (FR). 

Schrader G, Unger JG & Starfinger U (2010) Invasive alien plants in plant health: a review of the past ten years. 


Swiss Commission for Wild Plant Conservation CPS/SKEW (2006) http://www.cpsskew.ch/plantes_exotiques/information_sur_les_plantes_exotiques_envahissantes.html 

[Accessed on 

May 2010] 

Toussaint B, Mercier D, Bedouet F, Hendoux F, Duhamel F (2008) Flore de la Flandre française. Centre 

régional de phytosociologie agréé, Conservatoire Botanique national de Bailleul, Bailleul (FR). 

Warner PJ, Bossard CC, Brooks ML, DiTomaso JM, Hall JA, Howald AM, Johnson DW, Randall JM, Roye 

CL, Ryan MM & Stanton AE (2003) Criteria for categorizing invasive nonnative plants that threaten 

wildlands. http://www.cal-ipc.org/ip/ inventory/pdf/Criteria.pdf. [Accessed on October 2007]. 

Washington State Noxious Weed Control Board Website. http://your.kingcounty.gov/dnrp/library/water-andland/weeds/Brochures/Myriophyllum-heterophyllum.pdf 

[Accessed on May 2010]. 

Weber E (2003) Invasive Plant Species of the World – A Reference Guided to Environmental Weeds. CABI 

Publishing, Wallingford, UK, 548 p. 

Weber E, Gut D (2004) Assessing the risk of potentially invasive plant species in central Europe. Journal for 

Nature Conservation 3, 171-179. 

Zambettakis C & Magnanon S (2008) Liste des plantes vasculaires invasives, potentiellement invasives et à 

surveiller en région Basse-Normandie. Conservatoire Botanique National de Brest, Brest (FR). 



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Appendix - Prioritized list of invasive and potentially invasive species in France 

Species in bold are species which have been identified as priority for a national PRA 

1Indicates the region at risk: M=mediterranean, A=atlantic, C=continental. Letters between brackets means that the corresponding regions is not yet invaded but 

is at risk. 

2 

Score obtained with the W-G WRA: 3-21: low risk, 21-27: intermediate risk, 28-39: high risk 

3 

Type of impact: A=agriculture, E=environment. Letters between brackets means that the impact is only potential. 

4 

Agriophyte are species which occur in natural or semi-natural habitats while epocophytes are species restricted to disturbed habitats. 

Species name Reg. 1 Main habitats Score 2 I 3 Status 4 

Widespread invasive species (impact are reported in all three biogeographical regions of France) 

Ludwigia peploides (Kunth) P.H.Raven MAC Static or slow-flowing freshwater bodies 36 E Agriophyte 

Reynoutria japonica Houtt. MAC Riparian habitats, roadsides, wastelands 34 E Agriophyte 

Ludwigia grandiflora (Michx.) Greuter & Burdet MAC Static or slow-flowing freshwater bodies 33 E Agriophyte 

Ailanthus altissima (Mill.) Swingle MAC Ruderal habitats, riparian habitats 33 E Hemiagriophyte 

Acer negundo L. MAC Alluvial forests 32 E Agriophyte 

Elodea canadensis Michx. MAC Static or slow-flowing freshwater bodies 32 E Agriophyte 

Elodea nuttalii (Planch.) H.St.John MAC Static or slow-flowing freshwater bodies 32 E Agriophyte 

Paspalum distichum L. MAC Wetlands : riversides, riverbeds 32 AE Agriophyte 

Senecio inaequidens DC. MAC Ruderal habitats, pastures, dunes, rocks 31 E Hemiagriophyte 

Buddleja davidii Franch. MAC Ruderal habitats, riversides, forests 31 E Hemiagriophyte 

Reynoutria x bohemica Chrtek & Chrtkova MAC Riparian habitats, roadsides, wastelands 31 E Agriophyte 

Robinia pseudoacacia L. MAC Ruderal habitats, forest, calcareous or sandy grassland 31 E Agriophyte 

Ambrosia artemisiifolia L. MAC Arable fields, ruderal habitats, riverbeds 30 A(E) Epoecophyte 

Bidens frondosa L. MAC Riverbeds 30 E Agriophyte 

Phytolacca americana L. MAC Ruderal habitats, maize fields, riparian habitats, forest logging 29 AE Hemiagriophyte 

Impatiens glandulifera Royle MAC Riparian habitats, forest edges 29 E Agriophyte 

Lemna minuta Kunth MAC Static or slow-flowing freshwater bodies 29 E Agriophyte 

Conyza canadensis (L.) Cronquist MAC Arable fields, ruderal habitats, riverbeds 27 A Epoecophyte 

Abutilon theophrasti Medik. MAC Maize fields, wet wastelands, sandy river banks 25 A Epoecophyte 

Panicum capillare L. MAC Maize fields, ruderal habitats, riverbeds 25 A Epoecophyte 

Panicum dichotomiflorum Michx. MAC Maize fields, ruderal habitats, riverbeds 25 A Epoecophyte 

Panicum miliaceum L. MAC Maize fields, ruderal habitats 25 A Epoecophyte 

Amaranthus retroflexus L. MAC Cultivated fields, wastelands, ruderal habitats 25 A Epoecophyte 

Amaranthus hybridus L. MAC Cultivated fields, wastelands, ruderal habitats 23 A Epoecophyte 



135

Invasive species with impacts in one or two biogeographical regions in France (widespread species but still lacking in 

a large area of the country) 

Solidago gigantea Aiton MC Ruderal habitats, damp meadows, disturbed forest 38 E Agriophyte 

Solidago canadensis L. MC Ruderal habitats, damp meadows, disturbed forest 36 E Agriophyte 

Azolla filiculoides Lam. MA(C) Aquatic habitats : stagnant rivers, ponds, waterways 34 E Agriophyte 

Helianthus tuberosus L. M(A)C Alluvial floodplain, riverbed and riparian habitats 34 E Agriophyte 

Myriophyllum aquaticum (Vell.) Verdc. (M)AC Static or slow-flowing freshwater bodies 34 E Agriophyte 

Reynoutria sachalinensis (F.Schmidt) Nakai (M)AC Riparian habitats, roadsides, wastelands 34 E Agriophyte 

Hydrocotyle ranunculoides L.f. [M]AC Static or slow-flowing freshwater bodies 34 E Agriophyte 

Aster x salignus Willd. M(A)C Wetlands 33 E Agriophyte 

Cortaderia selloana (Schult. & Schult.f.) Asch. & Graebn. MA Wetlands, sandy soils, dunes 32 E Agriophyte 

Baccharis halimifolia L. MA Ruderal habitats, wetlands, saltmarshes 31 E Agriophyte 

Carpobrotus edulis (L.) N.E.Br. MA Coastal sand dunes and cliffs, salt marshes 31 E Agriophyte 

Lagarosiphon major (Ridl.) Moss (M)AC Static or slow-flowing freshwater bodies 31 E Agriophyte 

Pistia stratioides L. MA Static or slow-flowing freshwater bodies 30 E Agriophyte 

Cyperus esculentus var. leptostachyus Böck. AC Maize fields, riparian habitats 29 A Hemiagriophyte 

Sicyos angulata L. MA Maize fields, Riparian habitats 29 AE Agriophyte 

Egeria densa Planch. (M)AC Static or slow-flowing freshwater bodies 28 E Agriophyte 

Amorpha fruticosa L. MC Riparian habitats, alluvial forests, coastal estuaries, dunes 27 E Agriophyte 

Conyza sumatrensis (Retz.) E.Walker MA(C) Wastelands, Roadsides, ruderal habitats, riversides 27 A Epoecophyte 

Cabomba caroliniana A.Gray [M]AC Static or slow-flowing freshwater bodies 27 E Agriophyte 

Lindernia dubia (L.) Pennell (M)AC Edges of ponds, sandy riverbanks 26 E(A) Agriophyte 

Conyza bonariensis (L.) Cronquist MA(C) Arable fields, ruderal habitats, riverbeds 25 A Epoecophyte 

Regional invasive species (whose impacts are restricted to one biogeographical area) : more or less widespread in one 

region or very localized 

Artemisia verlotiorum Lamotte M(AC) Ruderal habitats, riparian habitats 36 E(A) Agriophyte 

Acacia dealbata Link M(A) Riparian habitats, wastelands, open forests 36 E Agriophyte 

Rudbeckia laciniata L. C Damp meadows, riparian habitats 36 E Agriophyte 

Aster lanceolatus Willd. (A)C Ruderal habitats, wetlands 35 E Agriophyte 

Prunus serotina Ehrh. (A)C Forests on acid soils 35 E Agriophyte 

Paspalum dilatatum Poir. M(AC) Riversides, wet meadows, ruderal habitats 34 E Agriophyte 

Prunus laurocerasus L. A(C) Wastelands, forests, human-modified forests, riparian habitats 33 E Agriophyte 

Lemna turionifera Landolt A(C) Aquatic habitats (eutrophic quite and warm waters) 33 E Agriophyte 



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Spartina x townsendii n-var. anglica (C.E.Hubb.) Lambinon & Maquet A Coastal (intertidal zone) 33 E Agriophyte 

Rosa rugosa Thunb. A Coastal dunes and sandy shores 33 E Agriophyte 

Spartina alterniflora Loisel. A Coastal (intertidal zone) 33 E Agriophyte 

Aster novi-belgii L. (A)C Ruderal habitats, wetlands 32 E Agriophyte 

Cotula coronopifolia L. M(A) Saline and freshwater marshes, swampedges, streambanks 32 E Agriophyte 

Helianthus x laetiflorus Pers. M Riverbeds, wastelands. 32 E Agriophyte 

Senecio angulatus L.f. M Coastal shrublands, ruderal habitats 32 E Agriophyte 

Cotoneaster dammeri C.K. Schenid. C Dry calcareaous grasslands 32 E Agriophyte 

Cotoneaster horizontalis Decne. C Dry calcareaous grasslands 32 E Agriophyte 

Gomphocarpus fruticosus (L.) R.Br. M Ruderal habitats, torrents of rivers, wetlands 31 E Agriophyte 

Carpobrotus aff. acinaciformis (L.) L.Bolus (M) Coastal sand dunes and cliffs, salt marshes 31 E Agriophyte 

Fallopia baldschuanica (Regel) Holub + F. aubertii M(AC) Riparian forests, riverbeds, dunes, ruderal habitats 31 E Agriophyte 

Lonicera japonica Thunb. ex Murray M(A) Wet forests, riparian habitats 31 E Agriophyte 

Sorghum halepense (L.) Pers. M(AC) Arable fields, ruderal habitats 31 A Epoecophyte 

Acacia saligna (Labill.) H.L.Wendl. M Grassland, coastal scrub and beaches, forests 31 E Agriophyte 

Opuntia ficus-indica (L.) Mill. m Dry grasslands, garrigue, rocks, ruderal habitats, dunes 31 E Agriophyte 

Crassula helmsii (Kirk) Cockayne A(C) Static or slow-flowing freshwater bodies, edges of ponds, lakes 31 E Agriophyte 

Parthenocissus inserta (A.Kern.) Fritsch M(AC) Riparian habitats, ruderal habitats, hedges 30 E Agriophyte 

Opuntia stricta (Haw.) Haw. M Dry grasslands, garrigue, rocks, ruderal habitats, dunes 30 E Agriophyte 

Aster squamatus (Spreng.) Hieron. M(AC) (Damp) wastelands, riparian habitats, (damp) cultivated fields 30 E Agriophyte 

Vitis riparia Michx. M Riparian habitats, alluvial forests 30 E Agriophyte 

Sesbania punicea Benth. M Riparian habitats, wetlands, ruderal habitats 30 E Agriophyte 

Eichhornia crassipes (Mart.) Solms M(A) Static or slow-flowing freshwater bodies 30 E Agriophyte 

Elide asparagoides (L.) KerguŽlen M Ruderal habitats, riparian habitats, edges of scrublands 30 E Agriophyte 

Oenothera glazioviana Micheli m Wastelands 30 E Hemiagriophyte 

Periploca graeca L. M Riparian habitats (Populus alba forest), dunes 29 E Agriophyte 

Humulus japonicus Siebold & Zucc. M[AC] Riverbeds, alluvial deposits rich in nutrients 29 E Agriophyte 

Cyperus eragrostis Lam. M(A) Riparian habitats and wetlands 29 E Agriophyte 

Heteranthera reniformis Ruiz & Pav. M Rice fields 29 A Epoecophyte 

Yucca filamentosa L. M Sand dunes, rocky shorelines 29 E Agriophyte 

Acacia longifolia (Andrews) Willd. M Riparian habitats, coastal dunes and shrubland 29 E Agriophyte 

Salpichroa origanifolia (Lam.) Baill. M(A) Coastal dunes, ruderal habitats 29 E Agriophyte 

Senecio deltoideus Less. M Wetlands 29 E Agriophyte 

Pyracantha pauciflora (Poir.) M.Roem. M Wastelands, human-modified forests 29 E Agriophyte 



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Alternanthera philoxeroides (Mart.) Griseb. [M]A Rivers, lakes, ponds irrigation canals, riparian habitats 29 E Agriophyte 

Elaeagnus angustifolia L. M(A) Ditches, sand dunes, salt meadows 29 E Agriophyte 

Yucca gloriosa L. M Dunes 29 E Agriophyte 

Tradescantia fluminensis Vell. M Riverbeds, fresh rocks. 28 E Agriophyte 

Rhus typhina L. C Riparian habitats, forests clearings, dry grasslands 28 E Agriophyte 

Solanum elaeagnifolium Cav. M Wastelands, potentially arable fields 28 A Epoecophyte 

Impatiens parviflora DC. (MA)C Moist to wet forests from floodplains to beech forests 27 E Agriophyte 

Xanthium italicum Moretti M(AC) Cultivated fields, riparian habitats, beaches 27 A Epoecophyte 

Acacia retinodes Schltr. M Forests, ruderal habitats, coastal sand dunes 27 E Agriophyte 

Heracleum mantegazzianum Sommier & Levier (MA)C Wastelands, riparian habitats, damp meadows, forest margins 27 E Agriophyte 

Bidens subalternans DC. M Cultivated fields, ruderal habitats 26 A Epoecophyte 

Bunias orientalis L. (A)C Ruderal habitats, crop edges, pastures and damp meadows 26 A Hemiagriophyte 

Cytisus striatus (Hill) Rothm. M(A) Scrublands, roadsides 26 E Agriophyte 

Oxalis pes-caprae L. M Ruderal habitats, riverbeds, dunes, shrublands 26 E Agriophyte 

Phyla filiformis (Schreider) Meikle M Damp meadows 26 E Agriophyte 

Rhododendron ponticum L. A Deciduous forests 26 E Agriophyte 

Eragrostis pectinacea (Michx.) Nees A Sandy soils in wastelands, along riverbeds, arable fields 26 E Agriophyte 

Medicago arborea L. M Coastal shrublands 25 E Agriophyte 

Setaria viridis (L.) P. Beauv. subsp. pycnocoma (Steud.) M(C) Arable fields, ruderal habitats 25 A Epoecophyte 

Akebia quinata Decne. [M]A Riparian habitats 25 E Agriophyte 

Setaria faberi F.Herm. [M]A[C] Roadsides, highways, potentially maize fields 25 A Epoecophyte 

Agave americana L. M Coastal cliffs, dunes, rocky places, distubed sites. 25 E Agriophyte 

Galega officinalis L. (MA)C Fresh grassland & pastures, ruderal habitats, river alluvium 25 AE Hemiagriophyte 

Echinochloa oryzoides (Ard.) Fritsch M Rice fields 25 A Epoecophyte 

Echinochloa phyllopogon (Stapf) Koso-Pol. M Rice fields 25 A Epoecophyte 

Heteranthera limosa (Sw.) Willd. M Rice fields 24 A Epoecophyte 

Hypericum majus (A. Gray) Britton C Etanges exondés 25 E Agriophyte 

Impatiens balfouri Hook.f. M(AC) Riparian habitats, alluvial forest, ruderal habitats 24 E Agriophyte 

Aristolochia sempervirens L. M Riparian woods 24 E Agriophyte 

Bothriochloa barbinodis (Lag.) Herter M Vineyards, ruderal habitats 24 A Epoecophyte 

Rumex cristatus DC. M Riparian habitats, damp arable fields 21 E Agriophyte 

Crocosmia x crocosmiiflora (Lemoine) N.E.Br. A Dunes, heathlands, grasslands, riparian habitats, ... 21 E Agriophyte 



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Modeling range changes of invasive alien and native expanding plant species in Armenia 

George Fayvush & Kamilla Tamanyan 

Institute of Botany, National Academy of Sciences of Armenia, Acharyan str. 1, Erevan 0063, 

Armenia, E-mail: gfayvush@yahoo.com, ktamanian@yahoo.com 

Introduction 

The article shows the research results of the spread of four invasive alien and 

four native expanding plants in Armenia (Ailanthus altissima, Echinocystis 

lobata, Impatiens glandulifera, Robinia pseudoacacia, and Astragalus 

galegiformis, Clematis orientalis, Silybum marianum, Tanacetum vulgare). 

Based on the current distribution of these species, the forecast of their further 

spread was considered using the DIVA-GIS and Bioclim software, with 

different climate change scenarios. Maps show the current distribution of the 

investigated species, with forecasted changes of their distribution. Temperature 

increase will allow the majority of species currently occupying insignificant 

territories in the lower mountainous belt to expand their distribution and habitat 

ranges considerably. The forecasted decrease in the quantity of precipitation 

will not hinder this process. 

These 8 species represent as a whole a threat to natural ecosystems and 

biodiversity, it is hence necessary to design and implement preventive 

measures. 

Armenia is a South Caucasian republic, neighbouring Georgia, Azerbaijan, Turkey and Iran. 

It is a landlocked country with a total area of 29,740 km 2 , at a distance of about 145 km from the 

Black Sea and 175 km from the Caspian Sea. It is mountainous country, having its lowest point 

at 375 m above sea level and culminating at 4095 m, with an average altitude of 1850 m. 

Variations in altitude have important effects on the climatic and landscape zones, and 

consequently on the vegetation of the country. 

In Armenia practically all main climate types from dry subtropical to cold alpine are 

observed. Rainfall is distributed unevenly with an average of 592 mm, in Ararat valley and 

Meghri region it is only 200-250 mm, while more than 1000 mm are recorded at the highest 

altitudes. 

The flora and vegetation of Armenia are very rich and diverse. More than 3600 species of 

vascular plants are present (123 of them are narrow local endemics), and all main vegetation 

types of the Caucasus are registered (excluding vegetation of wet subtropics). 

Changes (e.g. changes in the use of the landscape, road constructions, urbanization, etc.) are 

occurring fast and are seriously threatening both environment and accordingly human living 

conditions and the biodiversity including plant species and ecosystems as a whole. 

Current preliminary list of invasive alien and expanding species involves more than 100 taxa 

(Fayvush, 2008; Tamanyan, 2008). We have included in this list: (1) four species which are ab 

origine in Armenia, which in the last years enlarged considerably their range in Armenia and that 

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are known as invasive alien species in different countries of the World; and (2) four invasive 

alien species, which occurred in Armenia in the last 5 decades. We modeled potential shifts of 

distribution of 8 plant species according to different scenarios of climate change using the 

softwares DIVA-GIS and Bioclim. Those 8 species where chosen as a first examples, the work 

with other species will be continued. The main criterion for them was rather small area of current 

distribution and some time evidences of its enlargement in the last years. 

Modeling climate change in Armenia 

The climate change in the territory of Armenia is mostly conditioned by the influence of 

Global climate change. Climatologists have estimated possible temperature changes and amount 

of precipitation in the republic territory for the case scenarios of the greenhouse gas A2 and B2 

emission for the period of 2030, 2070 and 2100 using MAGICC/SCENGEN (5.3v2) and 

PRECIS softwares. It was shown that by the end of 21 st century the average temperature 

depending on the scenario can increase from 4,8 to 5,7 ˚С. Moreover the highest increase of the 

temperature is expected to be in the spring-summer period in the Southern and Central regions of 

the republic; the temperature increase in the North and East will be mild. The precipitation 

change forecast remains greatly indefinite – its decrease is supposed to be 1-27%. In the 

meantime a decrease of precipitation is expected in the summer period. In the fall-winter-spring 

period precipitation decrease is expected in foothills, but slight increase is expected in mountains 

(Second National report on Climate Change, 2010). 

Climate forecasts allow supposing the shift of the current ecological conditions up to 300-400 

meters in the mountain profile and to the increase of the aridity both the whole republic territory 

and especially its foothills and lower regions. The climate change here will also allow 

disturbances in the sustainable natural ecosystems. 

Modeling the change of the spread of invasive alien and expanding plant species 

All ecosystems of Armenia have been under anthropogenic influence for millennia, but in 

earlier times low human population and traditional regulated use of natural resources maintained 

the balance of ecosystems. Over the last 1000 years human impact on the land increased, mainly 

through deforestation and increased grazing pressure. The problems intensified since 1920 over 

recent years due to unprecedented population growth and urbanisation. The main consequence 

was loss of natural woodlands, grasslands and wetlands due to agriculture and overgrazing, 

urbanisation and road building, drainage and flooding, and afforestation. During last years (since 

1992) the economic and energy crisis mainly endangered Armenia‘s forests. Poor forest 

management combined with illegal wood cutting for fuel and construction has damaged about 

10% of the total forest area. At the same time, overgrazing has destroyed the grasslands 

surrounding the villages and degraded the formerly unspoilt pastures of remote mountains. 

Unfortunately, negative influence on the natural ecosystems continues to be the case 

nowadays. If at least some semblance of the order exists in Armenia in the forestry sector, the 

development of the mineral resource industry related to the open-cast mines of the natural 

mineral resources, infrastructure development and building of enormous number of accessory 

communications leads to degradation and full destroying of the natural ecosystems. 

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The Global climate change has its effect on occurring processes and also facilitates the spread 

of invasive alien species, changing existing ecosystems and creating new ecological niches 

which are becoming easily occupied by the species with large ecological amplitudes. In the 

meantime, the threat for many plant species consists in climate change itself – as changed 

conditions will not allow them to find appropriate niches and will lead to their total 

disappearance. The new edition of the Red Book of Armenia (2010) includes 452 species of 

plants, which are under threat due to the various reasons. For approximately one third of them 

climate change is the threat for their existence. 

Regarding invasive alien species having large ecological amplitude and easily adjusting to the 

new conditions, climate change will enlarge the possible area of distribution of many 

thermophilic invasive alien plants, which grow at present on restricted territory of the lower 

mountain belt in Armenia.. 

Here we present results of modeling the change of the spread of 8 invasive and expanding 

plant species. 

Ailanthus altissima (Mill.) Swingle is a very aggressive invasive species originating from Asia. It 

was introduced in 1940s for planting in settlements of Armenia. Then it escaped and in 1970s 

was found in disturbed and seminatural areas in neighborhood of different cities and towns. The 

distribution of this species in Armenia is shown in figure 1. These territories are still of limited 

distribution. The black territories show a possible spread of A. altissima to additional natural 

habitats. Ailanthus is quite hygrophilous, and forecasts of climate change only suggest increase 

of precipitation amounts in some alpine regions which are not suitable for the species. Supposed 

natural habitat will be relatively restricted, although forecasted change of the climatic conditions 

will allow this species to enlarge the area of distribution on humid habitats. 

Astragalus galegiformis L. is an expanding species, native to Armenia and the Caucasus. The 

distribution and possible spread of this species is shown in figure 2. Only two populations of this 

species were known before the 1980s – in forest edges and along streams of mountain river in 

the Northern Armenia. The habitats that this species colonize (roadsides, abandoned fields, 

disturbed habitats as well as meadows and steppes) have largely expanded in last years, and new 

populations of the plant have been found forming mono-dominant communities. Climate change 

modeling shows that this species will expand the current occupied habitats even more and will 

occupy larger areas. The conditions will become favorable for this species practically in the 

whole territory of the republic and in case of the spread of the seeds to further distance, the 

distribution of this species will appear to be much larger. It is necessary to note that this forecast 

has already started to be confirmed, as during field surveys in 2009 and 2010 new large 

populations of the species were found. The quality of pastures penetrated by this species is 

decreasing very rapidly. 

Silybum marianum (L.) Gaertn. – this Mediterranean species was known as weed on the 

territories of Georgia and Azerbajdzhan. In the first time it was found in 1967 in the South 

Armenia along roadside. Since then its range enlarged, and new populations were found in North 

and South Armenia (fig.3). Now it grows not only in disturbed areas, along roadside, in 

abandoned fields and in orchards, but also in natural communities – steppes and shibliak. Further 

spread of this species is forecasted. 

141 



Figure 1 - Distribution of Ailanthus altissima in Armenia (white-colored area – current 

situation, black – predicted distribution) 

Figure 2 - Distribution of Astragalus galegiformis in Armenia (white triangles – habitats 

known before 1980 th , black-colored areas – current situation, grey shaped territory – predicted 

distribution) 



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Figure 3 - Distribution of Silybum marianum in Armenia (white-colored areas – current 

situation, black – predicted distribution) 

Figure 4 - Predicted distribution of Robinia pseudoacacia in the Caucasus according to 

Kikodze et al., 2009) 



143

Robinia pseudoacacia L. originates from North-America and was used in artificial 

plantations in Armenia very broadly, especially along roads. At present it shows a weak invasive 

potential, but grows along streams and on wetlands in North and South-East Armenia. Kikodze 

et al. (2009) forecast the spread of this species in Armenia in the Ararat valley (fig.4). The 

present study disagrees with the forecast of Kikodze et al. (2009) in this part of the country since 

it is supposed that precipitation will decrease in most of Armenia, while this species is relatively 

hygrophilous. The current habitats invaded by this species and forecasted further spread are 

shown in the fig. 5. It supposes further spread of the species only in the North and South-East of 

the country where insignificant change of precipitation is expected. 

Clematis orientalis L. – native expanding species (it is known from Armenia, the Caucasus, 

Anatolia and Central Asia) was considered a rare species in Armenia (was even included in the 

Red book of Armenia, 1989). This plant currently spreads intensively in the central and southern 

parts of Armenia, showing a strong expanding potential. The habitats it colonizes which were 

known before 1990 and predicted distribution are shown on the map (fig 6). This liana used trees 

and shrubs mainly along rivers as natural habitat. Now besides that number of populations and 

area of distribution of this species are increased, the number of plants in known populations is 

extremely high, and sometimes it covers the ground along road and river sides. 

Figure 5 - Current and predicted distribution of Robinia pseudoacacia in Armenia (white 

triangles – current habitats, black area – predicted distribution) 

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Figure 6 - Current and predicted distribution of Clematis orientalis in Armenia (white 

triangles – habitats known before 1990, black – predicted distribution) 

Tanacetum vulgare L. is wide distributed in Temperate Eurasia, including the Caucasus, but 

was recorded in a few number of collections from disturbed habitats from northern part of 

Armenia (fig7). During the last years new big populations have registered in the North and South 

of Armenia (besides roadsides it was registered in steppes and meadows on forest edges). Further 

expansion of this species is forecasted. 

Figure 7 - Current and predicted distribution of Tanacetum vulgare in Armenia (whitecolored 

area – distribution of the species before 2000; black – predicted distribution) 



145

Echinocystis lobata (Michx.) Torr. & Gray (fig.8) and Impatiens glandulifera Royle (fig.9) – 

are widespread invasive species in Europe (www.nobanis.org). Currently suitable habitats are 

known predominantly in the North of Armenia. Climate change could allow those species to 

spread in Northern parts of Armenia where rather high amount of precipitation will remain. 

Figure 8 - Distribution of Echinocystis lobata in Armenia (white triangles – current habitats, 

black area – predicted distribution) 

Figure 9 - Distribution of Impatiens glandulifera in Armenia (white triangles – current 

habitats, black area – predicted distribution) 



146

Conclusions 

Preliminary results of the research on invasive alien and native expanding species started in 

Armenia in last years emphasize the importance of the problem. First of all it is necessary to 

monitor the current distribution of investigated species, which will provide the basis for the 

evaluation of their impacts on the natural ecosystems and biodiversity. 

The research carried out has shown the possibility of forecasting the changes in distribution of 

invasive alien and expanding native species in relation to climate change. These forecasts will 

also allow prioritizing species for estimating the level of the future threat to the natural 

ecosystems and biodiversity. 

References 

Fayvush G (2008) Investigation of invasive plant species in Armenia. Abstr. of 5 th European conference on 

biological invasions “Neobiota: towards a synthesis”, Prague (Czech Republic), 23-26 September 2008, 

p.72. 

Kikodze D, Memiadze N, Kharazishvilii D, Manvelidze Z, Mueller-Schaerer H (2009) The alien flora of Georgia. 

Tbilisi. 

Red Data Book of Armenian SSR (Plants) (1989). Yerevan. 

Second National Communication of the Republic of Armenia under the UN Framework Convention on Climate 

Change (2010) Yerevan. 

Tamanyan K (2008) Invasive plant species and agriculture in Armenia. Abstr. of 5 th European conference on 

biological invasions “Neobiota: towards a synthesis”, Prague (Czech Republic), 23-26 September 2008, p. 

114. 

Tamanyan K, Fayvush G, Nanagyulyan S, Danielyan T (eds.) (2010) The Red Book of plants of Armenian Republic 

(higher plants and fungi). Yerevan. 



147

Noxious and invasive weeds in Greece: Current status and legislation 

P C Lolas 

Professor, University of Thessaly, Dep. Agriculture, Crop Production and Rural Environment, 

Fytoko Str, GR-384 46, Volos, Greece, E-mail: lolaspet@agr.uth.gr 

Weeds, generally, are a major limiting factor in crop production almost in any 

agroecosystem. However, not all weeds are equally aggressive and important. 

Noxious and invasive alien weeds are two groups of weeds that not only 

threaten agricultural production but also in many cases cause serious economic, 

social and environmental losses. Invasive alien weeds and generally invasive 

alien plants damage native ecosystems as well. The importance of these weeds 

has been recognized in the U.S.A. and ‗‘noxious weed lists‘‘ with relevant 

legislation have been established by the United State Department of 

Agriculture and most U.S.A. States. Similarly, Australia and N. Zealand 

developed such lists and legislation (declared species). Also, in these and a 

number of other countries there are lists of invasive weeds and a lot of research 

is conducted. Despite all this, it is important to notice that in the EC and in 

Greece there is no any legislation concerning noxious and invasive weeds. 

Directive 2000/29/EC as amended by Directive 2009/118/EC concerning 

introduction into the EC of organisms harmful to plants or plant products does 

not include weeds. The EPPO Alert List is an indicative list developed by an 

international organization and not a mandatory legislation of the EC or of a 

Member State. Examples of local weeds to be characterized in Greece as 

noxious (Orobanche spp., Solanum eleagnifolium, Solanum rostratum), new 

weeds introduced in Greece (Ipomoea hederacea, Sida spinosa), or weeds 

(Ambrosia artemisiifolia, Solanum carolinense, Striga spp.) to be excluded 

from entering Greece are given. 

Due to the fact that there is no any national or EC legislation concerning 

noxious and invasive weeds such a legislation is urgently needed and 

suggested. The Greek Weed Science Society initiated a study to suggest to the 

Greek Department of Agriculture lists of noxious and invasive weeds in 

Greece. 

Noxious and invasive alien weeds importance 

Weeds constitute a significant limiting factor in crop production in almost all agroecosystems. 

Nowadays introductions of many plant species beyond their natural range are rising 

sharply because of increased trade, transport, travel and tourism, all associated with 

globalization. However, weeds are not equal in their importance and aggressiveness. Two groups 

of weeds that not only threaten agricultural production but cause also in many cases serious 

economic, social and environmental losses are noxious weeds and invasive alien weeds. Invasive 

alien plants damage native ecosystems as well. In the U.S.A. it is estimated that each year more 

than $1.3 billion are spent to fight noxious weeds and invasive alien plants are considered as the 

second great threat to the forests, after fire (Kaufman & Kaufman, 2007). Sala et al. (2000) 

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considered invasive alien species to be the second cause of global biodiversity loss after direct 

habitat destruction and to be among the top drivers of global environmental change. The 

importance of invasive alien plants has also been recognized by EPPO, and Alert Lists of 

invasive alien plant species have been developed (www.eppo.org). Estimates of losses due to 

noxious and / or invasive alien plants are not available for Greece. Indicative of the significance 

of noxious and invasive weeds are the noxious weed lists developed not only by the USDA 

Department of Agriculture (Federal List) but also by most U.S.A. States (State Lists), Australia 

and New Zealand (declared species), South Africa (major invaders, emerging invaders), and a 

number of other countries. To prevent and/or limit the impact of these weeds, considerable effort 

is allocated not only for their control but for research as well. 

Defining Noxious and Invasive alien weeds 

In this paper the meaning of noxious and invasive weeds follow the definitions of Radosevich 

et al. (2007), and Weber (2003). 

Noxious weed means any living stage, such as seeds and reproductive parts, of any parasitic or 

other plant of a kind, which is of foreign origin, is new to or not widely prevalent in an 

agroecosystem, and can directly or indirectly injure crops, other useful plants, livestock, or 

poultry or other interests of agriculture, including irrigation, navigation, the fish or wildlife 

resources or the public health (www.plants.usda. gov/java/noxious). 

Invasive alien weeds are species that do not naturally occur in a specific area (ecosystem) and 

whose introduction does or is likely to cause economic or environmental harm or harm to human 

health (Kaufman & Kaufman, 2007). 

A discussion with comments on the definition of invasive plants can be found in Brunel & 

Tison (2005). Also well recognized definitions of an invasive alien species is given by the 

Convention on Biological Diversity (CBD), Invasive alien species is an alien species (a species, 

subspecies, or lower taxon, introduced outside its natural past or present distribution; includes 

any part, gametes, seeds, eggs, or propagules of such species that might survive and 

subsequently reproduce), whose introduction and/or spread threaten biological diversity 

(www.cbd.int/decision/cop/?id=7197) 

Status in countries other than Greece 

Noxious and Invasive weeds regulations in the U.S.A. 

There are national and State (more than 40) lists for noxious weeds 

(www.plants.usda.gov/java/noxiousDriver). The species, the number (from 2 in one State to 242 

in California) and the characterization such as category A, B, C, or Primary, Secondary or simply 

Noxious or Restricted, differ from State to State. It is also important to notice that the same weed 

is noxious in one State but it is not in another and in the U.S.A list. In North Carolina and 

California where climatic conditions and weeds resemble those in Greece, noxious weeds are 

grouped in three categories, as A- not currently present or distribution is still limited (e.g. Avena 

sterilis), as B- distribution is still limited to portion of State (e.g. Tribulus terrestris), or as C- 

either already widespread or of special interest (e.g. Tribulus terrestris in California). In 

California, some weeds (both native or alien) listed as noxious are Cynodon dactylon – (C), 

149 



(present in other 38 States, noxious only in one, California), Avena sterilis (quarantine, present in 

5 States, noxious in 9 States and U.S.A list), Cardaria draba –(C), Cirsium arvense –(B), 

Cyperus spp.-(B) (present in 21 States, noxious in 4), Convolvulus arvensis –(C), (in 21 States), 

Sonchus spp. –A, Solanum eleagnifolium – B. All these weeds are very common and 

troublesome in Greece and it is suggested to be included in a noxious weed list in Greece. 

Noxious and invasive alien weeds regulations in Australia- New South Wales 

About two-thirds (1831) of the established alien plants in the Australian environment are 

escaped plants from gardens. They contribute substantially to the estimated $4 billion annual 

costs caused by weeds in agricultural ecosystems in Australia (Groves et al., 2005). 

As an example, in New South Wales the noxious weeds are regulated by the Noxious Weed Act 

1993 as amended in 2006. According to this regulation, noxious weeds (429 species) are grouped 

in 5 control classes (see the website of the Department of Primary Industry of New South Wales 

for further information) Class 1, State Prohibited Weeds, Class 2, Regionally Prohibited Weeds, 

Class 3, Regionally Controlled Weeds, Class 4, Locally Controlled Weeds, Class 5 Restricted 

plants. Class 1 and 2 weeds must be eradicated, Class 3 weeds must be continuously suppressed 

and destroyed, not propagated, not moved in other places, while Class 4 weeds are managed 

according to local Governments. For Class 5 weeds restrictions on their sale and movement are 

imposed. 

EPPO regulations 

EPPO elaborates lists of pests (including weeds and invasive alien species) whose regulation 

is relevant for the whole, or large parts of the EPPO region (www.eppo.org). The List A1 

includes pests not present in the EPPO region. The List A2 refers to pests present in the EPPO 

region but not widely distributed as absent from or not widely distributed in endangered areas in 

certain countries. Solanum eleagnifolium included in the A2 List is a weed present in Greece. 

Other EPPO Lists refer to invasive species including also the weeds Cyperus esculentus, Oxalis 

pes-caprae, Sicyos angulatus present in Greece. It is important, however, to notice that the EPPO 

Alert Lists are indicative lists developed by EPPO experts and not a mandatory legislation of the 

EC or of a Member State. 

Noxious and invasive weeds legislation in the E.U. 

Based on existing legislation, regulations and Directives (see below), one could say that in 

Europe, invasive alien plant species are considered not to constitute such a serious problem as in 

the United States, Australia, South Africa and other parts of the world. However, their negative 

economic, social and environmental impact is often highly damaging and likely to increase as a 

consequence of climate change, mobility of populations, transportation, increased tourism and 

travel activities, globalization of trade, and especially the opening of EU borders. 

Miller et al. (2006) provide a review of the existing legal and policy framework for Invasive 

Alien Species at international, EU and Member State levels. The authors, based on the 

information on the existing international, EU and national legal/policy frameworks, identify gaps 

in the existing EU invasive alien species legislation and make recommendations for filling such 

150 



gaps. At the national level, some countries (Germany, Great Britain, Portugal) have legislation 

and/or regulations aimed at preventing possession, transport, trade or release in the wild of 

specific invasive alien plants (www.issg.org). Information may be found either from National 

Plant Protection Organizations (i.e. Ministries of Agriculture) or from Ministries of Environment 

in individual countries. 

Habitat Directive 92/43/EEC 

The Habitat Directive 92/43/EEC provides amongst other provisions that individuals in 

general should be aware that under this Directive, deliberate introduction into the wild of non 

native species is regulated or prohibited, so as not to prejudice natural habitats or the wild native 

fauna and flora. The Directive has no any special statement for weeds generally and especially 

for noxious or invasive alien plants. 

Plant health Directive- EC Directive 2000/29 (amended by Directive 2002/89/EC) 

The Plant Health Directive concerns the ‗‘protective measures against the introduction into 

the Community of organisms harmful to plants or plant products and against their spread within 

the Community‘‘. Article 2 defines that the harmful organisms shall be considered to mean any 

species, strain or biotype of plant, animal or pathogenic agent injurious to plants or plant 

products. One of the most important measures in the Directive consists in listing the particularly 

dangerous harmful organisms whose introduction into the Community must be prohibited and 

also the harmful organisms whose introduction into the Member States when carried by certain 

plants or plant products must also be prohibited (listed in Annexes I-VII of the Directive). It is 

very important to notice and underline the fact that the Directive includes in the meaning of 

harmful organisms certain insects, mites, nematodes, bacteria, fungi, viruses, plants, but no 

weeds, except the parasitic plant Arceuthobium spp. originating out of Europe (Annex Ι Part Α). 

Recommendation 126/Council of Europe 

The recommendation was decided in the Convention on the Conservation of European 

Wildlife and Natural Habitats (Council of Europe) based on previous recommendations and on 

Article 8.h and Decision VI/23 of the 6 th Conference of the Parties of the Convention on 

Biological Diversity. The Recommendation suggests to contracting Parties 1. eradication of 

invasive alien plants which are not widespread and represent a threat at the regional scale or, 

when the invasion is taken at a late stage, containment or management action (appendix 1), 2. 

consider taking similar action against alien plant species having a high capacity of spread and 

presenting a very limited distribution (appendix 2). Plant species for which eradication or 

containment is recommended in Mediterranean countries are the weed Solanum eleagnifolium 

present in Greece and two alien species Hydrocotyle ranunculoides, Pueraria lobata not reported yet 

in Greece. 

European Strategy on Invasive Alien Species 

A number of European States have agreed to and approved the European Strategy on 

Invasive Alien Species concerning principles on invasive alien species which was approved by 

the Convention on Biological Diversity (Genovesi & Shine, 2004). Notice that it is not a 

legislation to be implemented and also does not explicitly refers to noxious weeds. 



151

Noxious and Invasive weeds legislation in Greece 

In Greece, as in other countries in Europe, the importance of noxious and / or invasive alien 

weeds and their serious negative impacts not only in agro ecosystems but also in natural 

ecosystems has not yet been realized. This can be inferred from the absence of any legislation or 

regulations for these two weed categories. The Presidential law 365/2002 adopts and complies 

with Directive EC Directive 2000/29. There is no any provision and /or criteria for 

characterizing, preventing introduction or eradicating noxious and / or invasive weeds. Therefore 

it is obvious that for these weeds it is essential that not only Greece but also EC centrally and the 

Member States (MS) adopt and harmonize all the necessary measurements for management of 

these weeds regarding characterization (Lists), prevention of their introduction from third 

countries, between MS, spreading inside of each MS, and of course the eradication in cases it is 

feasible economically and agriculturally (for example parasitic weeds not possible to be 

controlled by other means). 

List of proposed noxious alien weeds present in Greece 

In Greece more than 150 plant species are considered as important weeds causing economic 

losses (Lolas 2007). However, as already mentioned above there is not yet any 

legislation/regulation or official definition or List of noxious weeds in Greece. Arianoutsou et al. 

(2010) assessed 343 plant species as alien flora of Greece and its traits with no reference 

specifically to weeds, noxious or invasive. However, of the 343 alien taxa presented, 26 species 

characterized by the authors as naturalized alien species and of them, 13 with invasive behavior 

are included in the list of common weeds in Greece (Greek Weed Science Society). The authors 

report also that the species Oxalis pes-caprae, Erigeron (Conyza) bonariensis and Amaranthus 

albus, considered as weeds (Greek Weed Science Society), are typical cases of plants 

characterised as invasive, having established in almost all the habitat groups identified. It is 

interesting to note that 8 of the 13 species characterised by Arianoutsou et al. (2010) with 

invasive behaviour are proposed below to be included in the list of noxious weeds in Greece. 

More and specific information on invasive alien plant species for Europe and Greece can be 

found in the site of DAISIE European Invasive Alien Species Gateway (www.europe-aliens.org) 

Data on the environmental/economic impact for Oxalis pes-caprae as alien plant can be found 

in Vilà et al (2006) and as weed in Damanakis & Markaki (1990), while for the weeds Ipomoea 

hederacea, Panicum dichotomifolium and Sicyos angulatus in Anagnou-Veroniki et al. (2008) 

and for Galinsoga ciliata, Sida spinosa in Limperopoulou & Giannopolitis (2009). The weed 

species reported by Anagnou-Veroniki et al. (2008) and Limperopoulou & Giannopolitis 

(2009), known as very serious weeds in the USA, are currently under acclimatization in Greece 

but not widespread yet. The Greek Weed Science Society accepted the suggestion of the author 

to develop a List of weeds considered to be noxious under the conditions in Greece. Main 

criteria for a weed to be included in the List were competitiveness, ecological impact, 

propagation mechanism, control difficulty, extent of distribution, and in case of invasive weeds 

also their biological potential for invasion. The List will be sent to the Greek Ministry of 

Agriculture with the suggestion to develop relevant regulations. Some weeds (native and alien) 

that are proposed to be included in this List are: Ambrosia artemisiifolia (present but not yet 

widespread, Arianoutsou et al., 2010, Bergmeier, 2008) Cuscuta campestris, Orobanche spp., 

Ampelamus albidus, Arundo donax, Asphodelus aestivus, Avena sterilis, Carduus nutans, 

Centaurea diffusa, Centaurea solstitialis, Cirsium arvense, Conyza bonariensis, Conyza 

canadensis, Cyperus rotundus, Equisetum spp., Euphorbia nutans (present but not yet 

152 



widespread), Imperata cylindrica, Opuntia spp., Oryza sativa (red rice), Oxalis pes-caprae, 

Phragmites australis, Pteridium aquilinum, Solanum eleagnifolium, Solanum rostratum and 

Xanthium spinosum. All these weeds meet the above mentioned three criteria, are very common 

and troublesome causing serious losses in the habitats in which they are present (arable land, 

orchards, pastures, or natural ecosystems) and are reported as noxious in some other countries. 

List of proposed noxious alien weeds not present in Greece 

Some species, among many others, considered to be potentially noxious if they enter Greece 

are:Acroptilon repens, Eichhornia crassipes, Ipomoea spp. (except I. hederacea), Parthenium 

hysterophorus, Solanum carolinense, Solanum torvum, Solanum viarum, Striga spp. 

(holoparasite with no practically effective control method).These and other weeds are found in 

climates and habitats very similar to those in Greece, and it is therefore expected that any of 

them intentionally or unintentionally introduced in Greece would establish and spread to become 

serious and troublesome weeds in anthropogenic and /or natural ecosystems as in their original 

habitat. 

List of potential invasive alien weeds in Greece 

Although it is difficult to determine which biological characteristics are good indicators of 

invasiveness and there are no generally recognized characteristics that apply to plants that 

become invasive, such species often have some of the following characteristics: rapid growth 

and reproduction, ability to colonize disturbed or weedy areas, short growth cycle, early 

flowering and seeding, production of large quantities of seeds, effective vegetative propagation 

and spread, different phenology from native species allowing them to be strong competitors and 

to dominate. Many weeds share part of these characteristics that predispose them to becoming 

invasive (Dehnen-Schmutz, et al., 2007). Plants with some of the above features can be 

considered as potentially invasive. Some of these plants not yet present in Greece are Acroptilon 

repens, Cenchrus incertus (already present, Arianoutsou et al., 2010) Centaurea maculosa, C. 

iberica, Conyza albida, Eichhornia crassipes, Ipomoea spp. (except I. hederacea), Parthenium 

hysterophorus, Pueraria montana, Senna spp., Sesbania spp. This is not a conclusive list. 

Obviously, many other plant species may find their way to arrive in the country and become 

invasive. Some weeds are considered as both noxious not present in Greece and potentially 

invasive because they are reported as noxious in their original habitat and one cannot exclude the 

fact that these weeds may find their way, for example through seed lots, to arrive in Greece as it 

happened with so many other alien species until now. For certain weeds, as for example Striga 

spp. it is essential that all measures are taken so that the absolute prevention of its introduction in 

Greece be possible, or it is eradicated at its first observation before it spreads. 

Conclusions 

Noxious and invasive alien weeds constitute a serious threat to productivity in agro 

ecosystems and natural ecosystems. Local, national, European, and international coordinated 

action is needed to minimize their negative economic, social and environmental effects. It is now 

the time that EU and particularly Greece ensure legislation and regulations for noxious and 

invasive alien weeds so as to prevent and/or limit the introduction and spread of these plants and 

any other that are potentially invasive because of their known behaviour and negative impact 

elsewhere. 



153

Acknowledgments 

Sarah Brunel, Giuseppe Brundu and Ilhan Uremis are greatly acknowledged for their very 

useful, constructive and detailed comments which improved considerably the manuscript. 

References 

Anagnou-Veroniki M, Papaioannou –Souliotis P, Karanastasi E, & Giannopolitis CN (2010) New records of plant 

pests and weeds in Greece, 1990-2007 Hellenic Plant Protection Journal 1, 55-78 

Arianoutsou M, Bazos I, Delipetrou P. & Kokkoris Y (2010) The alien flora of Greece: taxonomy, life traits and 

habitat preferences. Biology Invasions 12, 3525–3549 

Bergmeier E (2008) Ambrosia artemisiifolia L.; Hesperis matronalis subsp. cladotricha (Borbαs) Hayek. In: 

Greuter, W. & Raus, Th. (eds.), Med-Checklist Notulae, 27. – Willdenowia 38, 466-467. 

Brunel S & Tison JM (2005) A method of selection and hierarchisation of the invasive and potentially invasive 

plants in the continental Mediterranean France. p 49-64 In Brunel S (ed). Invasive plants in the Mediterranean 

type regions of the world. Proceedings, pp. 428 

Damanakis M, & Markaki M (1990) Studies on the biology of Oxalis pes-caprae L. under field conditions in 

Greece. Zizaniology 2, 145-154 

Dehnen-Schmutz K, Touza A, Perrings C. & Williamson M. (2007). The horticultural trade and ornamental plant 

invasions in Britain. Conservation Biology 21, 224–231. 

Genovesi P. & Shine C. 2004. European Strategy on Invasive Alien Species. Nature and Environment n 137. 

Council of Europe publishing, Strasbourg, pp 67. 

Groves RH, Boden R & Lonsdale WM (2005) Jumping the Garden Fence: Invasive garden plants in Australia and 

their environmental and agricultural impacts, a CSIRO report for WWF-Australia. 173. 

Kaufman SR & Kaufman W. (2007) Invasive plants. A Guide to Identification and the Impacts and Control of 

Common North American Species Stackpole books, pp.458. 

Lolas P (2007) Weed Science, Weeds, Herbicides, Fate and behaviour in the environment, Synchrony paideia, 

Thessaloniki, pp. 628. 

Lymperopoulou S. & Giannopolitis CN 2009) Galinsoga ciliata (Raf.) S.F.Blake and Sida spinosa L., two new 

weed records from Greece. Hellenic Plant Protection Journal 2, 37-4 

Miller, C, Kettunen, M. & Shine C. (2006) Scope options for EU action on invasive alien species (IAS) Final report 

for the European Commission. Institute for European Environmental Policy (IEEP), Brussels, Belgium. 109 pp + 

Annexes. 

Radosevich, SR, Holt, J S & Ghersa C M (2007) Biology of weeds and invasive plants. 3d ed. Wiley, pp. 454. 

Sala OE, Chapin III FS, Armesto JJ, Berlow R, Bloomfield J, Dirzo R, Huber-Sanwald E, Huenneke LF, Jackson 

RB, Kinzig A, Leemans R, Lodge D, Mooney HA, Oesterheld M, Poff NL, Sykes MT, Walker BH, Walker M, 

& Wall DH (2000). Global biodiversity scenarios for the year 2100. Science 287, 1770-1774 

Vilà M, Tessier M, Suehs CM, Brundu G, Carta L, Galanidis A, Lambdon P, Manca M, Medail F, Moragues E, 

Traveset A, Troumbis AY, Hulme PE (2006) Local and regional assessments of the impacts of plant invaders on 

vegetation structure and soil properties of Mediterranean islands. Journal of Biogeography 33, 853–861 

Weber E (2003) Invasive plant species of the world. A reference guide to Environmental weeds. CABI Publishing, 

Wallingford 

Internet sites, (date of consultation, 12/12/2010) 

CBD, www.cbd.int/decision/cop/?id=7197 

Council of Europe, https://wcd.coe.int/wcd/ViewDoc.jsp?Ref=Rec(2007)126&Language=lanEnglish&Ver= 

original&Site=COE&BackColorInternet=DBDCF2&BackColorIntranet=FDC864&BackColorLogged=FDC864 

DAISIE, www.europe-aliens.org 

Dep. of Primary Industry of New South Wales www.dpi.nsw.gov.au/agriculture/pests-weeds/weeds/definition 

EPPO, www.eppo.org ; 

GISD, www.issg.org/database/reference/index.asp 

Greek Weed Science Society, www.eze.org.gr 

IPCC, www.ipcc.ch/pdf/glossary/ar4-wg2.pdf ; 

USDA, www.plants.usda. gov/java/noxious 



154

A tales of two islands: comparison between the exotic flora of Corsica and Sardinia 

Daniel Jeanmonod 1 and Giuseppe Brundu 2 

1 Laboratory of Plant systematic and biodiversity, University of Geneva, Conservatoire et jardin 

botaniques de la Ville de Genève, Switzerland 

E-mail : Daniel.jeanmonod@ville-ge.ch 

2 Department of Botany, Ecology and Geology, University of Sassari, Italy 


Alien plant species have been introduced to Europe throughout history. There are regions, such 

as the Mediterranean basin islands, where for thousands of years man has been responsible for 

the spread of ever-increasing numbers of plants taxa, introduced for different purposes or quite 

often entered accidentally and rarely controlled. The two geographically close islands of Corsica 

and Sardinia share similar features concerning the geological history, the native vegetation, the 

endemism rate and the land use dynamics in the coastal areas and surrounding islets. 

Nevertheless there are also specific differences, mainly in the inner mountain areas, where 

average altitude is markedly higher in Corsica than in Sardinia. 

These insular systems represent a local hotspot for native biodiversity and an area of 

international interest for habitats and nature conservation. 

Coastal areas of both islands also share similar features concerning the composition of their 

exotic floras and the distribution patterns and impacts of the main invasive aliens, such as 

Carpobrotus spp., Cortaderia selloana, Oxalis pes-caprae, to mention a few. Due to the 

geographical position, the two islands are in fact interconnected and there are frequent trade 

exchanges and tourism flux between them, thus increasing the probability for similar sensitive 

habitats to be invaded by the same invasive taxa. In this paper we compare the naturalised and 

casual alien plants of the islands of Corsica and Sardinia, highlighting common features and the 

main differences, with some indications for management. 



155

Nouvelle espèce menaçant la biodiversité au Maroc: Verbesina encelioides (Asteraceae) 

A Taleb, M Bouhache & B El Mfadi 

Institut Agronomique et Vétérinaire Hassan II, B.P. 6202 Rabat-Instituts, Rabat, Maroc, Emails 

: a.taleb@iav.ac.ma; abdeltaleb@yahoo.fr; m.bouhache@iav.ac.ma; 

m.bouhache@gmail.com 

Introduction 

Verbesina encelioides (Cav.) Benth. et Hook. ex Gray est une plante exotique 

récemment introduite au Maroc. Elle a envahi totalement le périmètre de 

Souss–Massa (région d‘Agadir) et depuis, elle s'est propagée vers d'autres 

régions : Safi, Rabat, Larache, Sefrou, Fès. Le présent travail a été entrepris 

dans le but d'évaluer l'état d'infestation, de décrire les caractéristiques morphoécologiques 

de V. encelioides, de faire le point sur les dangers inhérents à cette 

nouvelle plante et d‘étudier le comportement des akènes vis-à-vis de certaines 

variantes de l'environnement : la température, la photopériode, le stress 

hydrique et la profondeur d'enfouissement. Les enquêtes ont permis de mettre 

en relief l'importance sa présence dans des milieux plus ou moins perturbés par 

l'homme ainsi que son effet attractif sur la mouche blanche. 

Le test de viabilité a révélé une moyenne de 92% d‘akènes viables. La 

cinétique d‘imbibition est rapide et importante pendant les premières 12 heures 

d‘incubation et elle se ralentit au delà. Les essais de germination ont démontré 

la capacité des akènes à germer dans la gamme thermique allant de 8þC à 35þC 

avec un optimum de 15þC/25þC, et une indifférence totale vis-à-vis de la 

lumière. Aussi, la diminution du potentiel hydrique jusqu‘à -0,6 MPa n‘affecte 

pas la capacité de germination des akènes. Cependant, la diminution du 

potentiel hydrique de -0,6 MPa à -1,3 MPa engendre une chute du pourcentage 

de germination. 

L‘émergence des plantules a été remarquée jusqu‘à 3,5 cm de profondeur. Le 

maximum des émergences a été enregistré à la profondeur de 1,5 cm suivie par 

0 et 2,5 cm et 3,5 cm de profondeur. A partir de 7 cm de profondeur, aucune 

plantule n‘émerge ? 

Concerne sa croissance et son développement, V. encelioides parvient à 

accomplir son cycle de développement, de l‘émergence à la maturité des 

premiers akènes, en 80 jours. Durant son cycle, elle favorise la croissance de la 

partie aérienne et elle investit plus dans la formation de la tige et des rameaux 

dans un premier temps, les inflorescences apparaissent ensuite à partir du stade 

floraison. La production des semences est importante et échelonnée dans le 

temps. 

A l‘instar des autres pays du bassin méditerranéen, le Maroc n‘est pas à l‘abri des invasions 

biologiques. Ces dernières années a en effet été noté l‘apparition de nouvelles espèces au sein de 

la flore marocaine (Ameur & Bouhache, 1994; Qorchi & Taleb, 1997; Tanji & Taleb, 1997; 

Taleb & Bouhache, 2005). 

156 



Verbesina encelioides (Cav.) Benth. et Hook. ex Gray a été introduite au Maroc et 

spécialement dans la région du Souss (Agadir) vers les années 90. C‘est une espèce dotée d‘une 

large amplitude écologique. Elle s‘accommode avec sa nouvelle aire d‘introduction et s‘y 

propage naturellement (Kaul et Mangal, 1987). La première phase de son invasion est agressive 

et rapide grâce à sa capacité à fleurir et à produire des semences durant toute l‘année (Tuvia, 

1998). Elle commence par l‘occupation des terrains incultes et les bordures de routes et s‘étend 

ensuite aux terrains cultivés, toutes cultures confondues (Kaul & Mangal, 1987; Tuvia, 1998). 

C‘est une plante annuelle, nitrophile, mésotherme, caractérisée par une grande souplesse et 

une grande plasticité de germination et de croissance. Dans son aire d‘origine, elle pousse dans 

différents types de sols et sous des conditions de température et d‘humidité très variables (Kaul 

& Mangal, 1987). V. encelioides occasionne des nuisances diverses. En plus de la compétition 

avec d‘autres plantes (Grichar & Sestak, 1998), elle peut exercer un effet allélopathique en 

libérant des toxines dans le sol (Usha, 1987). Elle est aussi hautement toxique vis-à-vis du bétail 

en provoquant un arrêt rapide de la respiration (Baker et al., 1992; Campero et al., 1996). 

Néanmoins, le danger le plus redoutable est celui de la transmission du virus de la maladie 

bronzée de la tomate, TSWV. Elle héberge à la fois le virus et son vecteur, à savoir les thrips 

(Cho et al., 1988; Bautista & Mau, 1994; Forrest et al., 1996). Le TSWV s‘attaque à une large 

gamme d‘espèces d‘intérêt économique; les Solanaceae, les légumineuses, les plantes 

ornementales, etc. Cette maladie peut avoir un caractère épidémiologique et envahir des surfaces 

culturales très étendues (Forrest et al., 1996). 

Compte tenu de ces données et en absence de toute étude préalable sur cette espèce au Maroc, 

une étude a été entreprise dans le but d'évaluer l'état d'infestation, de décrire les caractéristiques 

morpho-écologiques de V. encelioides, de faire le point sur les dangers inhérents à cette nouvelle 

plante et d‘étudier le comportement des akènes vis-à-vis de certaines variantes de 

l'environnement: la température, la photopériode, le stress hydrique et la profondeur 

d'enfouissement. 

Historique 

Le genre Verbesina L. appartient à la famille des Asteraceae (Composées). Ce genre 

comprend plus de 60 espèces originaires principalement des régions chaudes (Amérique boréale 

et australe). Verbesina encelioides est connue sous plusieurs noms : Butteer daisy, Golden 

Crown daisy, Grown beard, American dogweed, South africain daisy. 

La plante a été décrite pour la première fois par le botaniste espagnol Antonio José Cavanilles 

(1745-1804) mais sous un autre genre. Après, Georges Benthan (1800-1884) et Hooker (1817- 

1911) ont placé la plante dans sa position taxonomique actuelle. Cependant, son nom n'a été 

publié officiellement qu'en 1876 quand le botaniste américain Asa Gray (1810-1888) l'a citée 

dans son article « Botany of California ». 



157

Matériel et méthodes 

1. Matériel végétal 

Pour les essais de viabilité, d‘imbibitions et de germination, les semences utilisées 

proviennent de la région d‘Agadir (Souss), et plus précisément des zones de Khmiss Aït Amira 

et de Biougra. La collecte est faite manuellement et d‘une manière aléatoire sur des pieds en fin 

de maturité. Après deux jours d‘exposition à l‘air libre au laboratoire afin d‘éliminer toute trace 

d‘eau à la surface des akènes, ces derniers ont été conservés dans des sachets en papier dans un 

milieu sec et à température ambiante jusqu'à leur utilisation. 

Il est à noter qu‘au sein de la zone de collecte, les prospections et les prélèvements ont été 

effectués dans différentes situations : terres incultes, champ de carotte, champ de maïs, serre 

vide, etc. 

Pour l‘étude morpho-écologique, les plantes ont été collectées dans les différentes régions du 

Maroc ou l‘espèce a été signalée. 

2. Test de viabilité 

Ce test est entrepris dans le but d‘estimer le pourcentage des akènes viables et non viables au 

sein de 6 lots de 200 akènes, correspondant aux différentes stations de collecte. 

Pour la réalisation de ce test, nous avons utilisé le chlorure du tetrazolium à 1% (Chlorure de 

2,3,5-triphenyl tetrazolium). La viabilité des semences est appréciée d‘après la coloration 

rougeâtre de l‘embryon observé sous une loupe binoculaire. Les observations sont faites à un 

intervalle de 4 heures (Weber & Wiesner, 1980). 

3. Test d’imbibition 

Il consiste à mettre les semences sur un papier filtre, Wathman Nþ1, qui surmonte une couche 

d‘éponge de 3 mm d‘épaisseur saturée d‘eau distillée. L‘ensemble est mis dans des boites de 

pétri préalablement stérilisées. 

Nous avons utilisé 4 lots de semences de 50 akènes qui ont été pesés au préalable. Des 

mesures de poids ont été faites après : 0,5 h, 1 h, 2 h, 4 h, 6 h, 8 h, 10 h, 12 h, 24 h, 36 h, 48 h, 60 

h et 72 h du début de test. Le test d‘imbibition a été mené au laboratoire à température ambiante 

et dans des conditions hydriques non limitantes. 

4. Essais de germination sous des conditions contrôlées : 

Ces essais ont été entrepris dans le but de mieux connaître le comportement et les exigences 

des akènes de V. encelioides vis-à-vis de la température, de la lumière et de l‘eau. 



158

Les régimes thermiques 

Dans le choix des régimes thermiques, nous avons essayé de respecter les critères suivants : 

- tester des degrés de température à l‘intérieur de la gamme permettant la 

germination de V. encelioides qui s‘étale de 5þC à 40þC (Mahmoud et al., 1984), 

ainsi que des extrêmes thermiques ; 

- présenter trois régimes thermiques : froid (hiver), frais (printemps) et chaud (été). 

La photopériode adoptée est de 12 h / 12 h. 

Traitements Température °C 

Jour Nuit 

T 1 10 8 

T 2 15 10 

T 3 25 15 

T 4 30 17 

T 5 35 20 

T 6 40 22 

Les régimes hydriques 

Cet essai vise à étudier l‘effet du stress hydrique et la détermination du potentiel critique 

minimal permettant la germination des semences de V. encelioides dans des conditions 

spécifiques. 

Pour simuler les différents potentiels hydriques nous avons utilisé le polyéthylène glycol 

20.000 (PEG 20.000). Le PEG 20.000 présente l‘avantage, par rapport aux autres agents 

osmotiques (i.e. les sels, monitol, etc.) d‘être inerte, non toxique, et non absorbable par les 

semences (Yessef, 1984). 

Les niveaux du potentiel hydrique adoptés sont les suivants (Yessef, 1984) : 

Solution Concentration du PEG en Potentiel hydrique Potentiel 

g/l d’eau distillée 

(MPa) hydrique (bar) 

S 1 0 -0.03 -0.3 

S 2 160 -0.3 -3 

S 3 210 -0.6 -6 

S 4 270 -0.9 -9 

S 5 340 -1.3 -13 

Emergence à différentes profondeurs d’enfouissement 

Cet essai est conduit dans le but d‘étudier le comportement des akènes en termes d'émergence 

en fonction de la profondeur du semis. Il a été conduit dans une parcelle du jardin botanique de 

l‘Institut Agronomique et Vétérinaire Hassan II à Rabat. 



159

Le semis a été fait dans des pots de 16 cm de diamètre et 22 cm de hauteur confectionnés à 

partir de bouteilles en plastique de 5 l perforées à leur base pour évacuer l‘excès d‘eau. Le sol a 

été stérilisé à l‘autoclave pendant 4 h, avec un intervalle de 24 h entre les 2 h, sous une pression 

de 1 bar. 

Les différentes profondeurs ont été choisies sur la base des études qui ont été faites par 

d‘autres auteurs, dans d‘autres conditions et avec des populations autochtones de V. encelioides, 

à savoir Kaul & Mangal, (1987). Les profondeurs de semis testées sont : 0 ; 1 ; 2,5 ; 3,5 ; 7 ; 14 

et 20 cm. 

Croissance et développement des plants de V. encelioides 

Le but de cet essai est de décrire la croissance et le développement des plants de 

V. encelioides à travers un ensemble d‘observations et de paramètres mesurés et calculés. 

Le semis a été fait à une profondeur de 2 cm dans des pots confectionnés, du même type que 

ceux de l‘essai précédent, à raison de 10 akènes par pots. La terre utilisée a été stérilisée au 

préalable à l‘autoclave. Une fois que les akènes ont germés et que les plantules se sont 

stabilisées, nous avons gardé une seule plantule par pot afin d‘éviter toute compétition pouvant 

s‘établir entre les plantules au dépend de leur croissance. 

Nous avons fixé cinq stades végétatifs comme repère pour faire les prélèvements et les 

observations: 

- Stade plantule. 

Résultats 

- Stade rosette. 

- Stade redressement. 

- Stade floraison. 

- Stade maturité. 

1. Origine de son introduction 

V. encelioides a été rencontrée aux USA, en Argentine, au Mexique, au Moyen Orient, en 

Algérie (observée à Mostaganem en 1874 par Pomel et puis par D‘Alleizette en 1919) et au 

Maroc à la fin des années 90. Cette espèce n'a jamais été signalée dans le catalogue des plantes 

du Maroc (Jahandiez & Maire, 1931-1934). Elle vient s'ajouter aux 12 espèces introduites ces 

dernières années au Maroc (Tanji & Taleb, 1997 ; Taleb & Bouhache, 2005). 

L'origine de l‘introduction de V. encelioides est inconnue. Au Maroc, sa date d'apparition 

remonte à plus de 10 ans dans la zone de Souss–Massa (Sud du Maroc). Il est soupçonné qu'elle 

y ait été introduite comme plante ornementale. Les premiers foyers ont été constatés aux 

alentours de l'ancien aéroport d'Inzegane et puis elle a envahi tout le périmètre. Elle s'installe 

dans les entourages des habitations, les terrains incultes et les terrains cultivés. Certaines 



160

personnes interrogées déclarent qu'elle aurait été introduite avec le fumier, d'autres ajoutent que 

les akènes sont disséminés par le vent et l'eau d'irrigation pompée à partir du barrage. 

2. Description de la population marocaine de V. encelioides 

Des observations et des mesures effectuées sur un ensemble de pieds prélevés dans les 

différentes stations ont permis de décrire cette espèce végétale et de déterminer ses particularités. 

V. encelioides se présente comme une plante herbacée d'un vert grisâtre. La racine est pivotante 

pouvant dépasser les 30 cm de longueur, associée à un système de racines fasciculées très 

développé. A signaler, la présence, parfois, d'une racine latérale, de taille moyenne, prenant 

naissance à partir de la zone subérifiée de la racine principale et qui se développe juste au 

dessous de la surface du sol. 

La tige est très ramifiée et comporte jusqu'à 17 rameaux. Sa longueur atteint, pour certains 

pieds, les 130 cm. Les feuilles basales de la tige et des rameaux sont opposées, les autres sont 

alternes. Les capitules, ou inflorescences, se situent aux extrémités de la tige et des rameaux à 

différents degrés de maturité. Sur le même pied, on trouve des capitules immatures, d'autres en 

phase d'épanouissement et d'autres en début ou en fin de maturité des akènes. Ils sont supportés 

par des pédoncules dont la longueur varie en fonction de position des capitules, ceux du centre 

sont plus longs que les périphériques. Grossièrement, le nombre moyen des capitules par pieds 

est de 36, mais de 6 à 470 capitules ont été dénombrés. Chacun est constitué de deux types de 

fleurs : des fleurs périphériques, radiées, jaunes et triplement dentées dont le nombre varie de 13 

à 21 par capitule ; et des fleurs centrales, tubulées, et hermaphrodites constituées par un long 

tube partiellement soudé. Leur nombre varie de 145 à 200, avec une moyenne de 167. Chacune 

de ces fleurs tubulées est associée à une écaille qui s'attache à sa base. L'ensemble est inséré au 

niveau du réceptacle floral. Les deux types de fleurs produisent des akènes. Les akènes issus des 

fleurs radiées sont noirs, côniformes et allongés, non ailés, durs avec une surface rigoureuse et 

mesurent environ 4 mm de longueur. En revanche, les akènes issus des fleurs tubulées sont 

pourvus de deux ailes de couleur beige claire. Leur nombre peut dépasser les 200 akènes par 

capitule avec une moyenne de 180. Il existe un polymorphisme relativement léger chez ce type 

d'akènes, on y trouve des akènes possédant trois, quatre, ou cinq ailes. 

3. Infestation et répartition 

Les enquêtes ont permis de mettre en relief l'importance de l'infestation et de la présence de la 

plante dans des milieux plus ou moins perturbés par l'homme ainsi que son effet attractif sur la 

mouche blanche. 

V. encelioides se rencontre dans les régions de Souss (Agadir), de Safi (Had Hrara), de 

Taroudant, de Rabat (région de Témara), d‘Assila, de Larache, de Tétouan (Nord du Maroc), de 

Marrakech et de l‘Oriental. 

4. Importance agronomique 

Des enquêtes lors des relevés ont montré que V. enceloides commence à envahir les champs 

cultivés (maïs, cultures sous serres). De plus, elle est susceptible de constituer un réservoir pour 

une gamme diversifiée d'agents de maladies et de viroses de plusieurs plantes cultivées, à savoir : 

- Cucumber mosaic (cucumovirus), 

- Dahlia mosaic (caulimovirus), 



161

- Hogweed mosaic nepovirus), 

- Pepper veinal mottle (potyvirus), 

- Strawberry latent ringspot (nepovirus), 

- Tomato Spotted Wilt Virus (Tospovirus) 

Des études ont montré qu'au moment de la floraison, le thrips (Franfliniella occidentalis) 

préfère se nourrir et pondre sur V. encelioides plutôt que sur d'autres plantes comme Datura 

stramonium L., d'où le risque de transmission du Virus Tomato Spotted Wilt (Tospovirus) 

(Bautista & Mau, 1994; Bautista et al., 1995; Mitchell & Smith, 1996). 

De plus, V. enceloides a causé des cas de toxicité du bétail au Maroc cette année, ce qui a été 

rapporté aux USA (une dose de 5 g de solution de la plante par Kg de poids vif administré à un 

mouton le tue après 72 heures). Ainsi, l'animal intoxiqué présente les symptômes suivants : 

- perturbation de la fonction respiratoire, 

- forts exsudats des narines, 

- hydrothorax avec 2 à 3 l de liquide thoracique avec des traces de fibrine, 

- œdème dans les poumons. 

Cette toxicité est due à la concentration (0,08%) de galégine dans la plante (Keeler et al., 

1992; Lopez et al., 1996). 

Figure 1 - Evolution du gain de poids relatif en fonction du temps pour les akènes de Verbesina 

encelioides 



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5. Test de viabilité 

Les pourcentages de viabilité (moyenne 92%) des akènes reflètent leur grande capacité 

germinative. Tenant compte de la production élevée par pied (moyenne de 6480 d‘akènes), nous 

pouvons déduire qu‘une fraction importante d‘akènes est viable et capable de germer lorsque les 

conditions environnementales sont adéquates. 

6. Test d’imbibition 

Le processus d‘imbibition (d‘absorption d‘eau) est entamé dès le premier contact eau-akène. La 

cinétique d‘imbibition est rapide et importante pendant les premières 12 heures d‘incubation et 

elle se ralentit au-delà. Vers 72 heures, le gain de poids est de 2,7 fois (Fig. 1). 

Figure 2 - Pourcentages cumulés de la germination des akènes en fonction de différents régimes 

thermiques (T1: 8þC/10þC; T2: 10þC/15þC; T3: 15°C/25°C; T4: 17þC/30þC; T5: 20þC/35þC) 

7. Essais de germination en conditions contrôlées 

Les régimes thermiques 

Ces essais ont été entrepris dans le but de mieux connaître le comportement et les exigences 

des akènes de V. encelioides vis-à-vis de la température, de la lumière et de l‘eau. 

Les essais de germination ont démontré la capacité des akènes à germer dans la gamme 

thermique allant de 8þC à 35þC avec un optimum de 15þC/25þC (Fig. 2) et une indifférence 

totale vis-à-vis de la lumière. 

Les régimes hydriques 

La diminution du potentiel hydrique jusqu‘a -0,6 MPa n‘affecte pas la capacité de 

germination des akènes. Cependant, la diminution du potentiel hydrique de -0,6 MPa à -1,3 MPa 

engendre une chute du pourcentage de germination (Fig. 3). 



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Figure 3 - Evolution de la germination de Verbesina encelioides en fonction de la diminution du 

potentiel hydrique (à quoi correspondent S1, S2, S3, S4 et S5 ?) 

Essai d'émergence à différentes profondeurs d’enfouissement 

En ce qui concerne la profondeur de semis, la levée des plantules a été initiée 8 jours après 

semis. Parmi les profondeurs testées, uniquement quatre se sont révélées positives vis-à-vis de 

l‘émergence (à 0 ; 1,5 ; 2,5 et 3,5 cm de profondeur) (Fig. 4). 

L‘émergence des plantules a été remarquée jusqu‘à 3,5 cm de profondeur. Le maximum des 

émergences a été enregistré au niveau de la profondeur 1,5 cm suivie par 0 et 2,5 cm et ensuite 

3,5 cm. A partir de 7 cm de profondeur le pourcentage d‘émergence devient nulle. 

Croissance et développement 

Concernant sa croissance et son développement, V. encelioides parvient à accomplir son 

cycle de développement, de l‘émergence à la maturité des premiers akènes, en 80 jours. Durant 

son cycle, elle favorise la croissance de la partie aérienne et elle investit plus dans la formation 

de la tige et des rameaux dans un premier temps, les inflorescences apparaissent ensuite à partir 

du stade floraison. 

Du 69 au 71ième jour approximativement, les premiers capitules éclos commencent à perdre 

les fleurs périphériques et la formation des akènes est entamée. Ainsi, la première vague des 

akènes mûrs est enregistrée 80 jours après l'émergence des plantules. La production des 

semences est importante et échelonnée dans le temps. 

Dans la plupart des zones prospectées, V. encelioides existe sous différents stades 

phénologiques ; du stade plantule au stade fin de maturité. Ceci témoigne de l'échelonnement de 

la croissance et du développement de cette espèce et de sa capacité à germer, à fleurir et à 

produire des semences tout au long de l'année. 



164

Figure 4 - Evolution des pourcentages d‘émergence de Verbesina encelioides en fonction de la 

profondeur du semis 

Discussion 

L‘extrapolation de ces résultats de terrain met en les possibilités d‘établissement et de 

prolifération de V. enceloides. 

En se basant sur le classement des différentes régions du Maroc dans le système climatique 

d‘Emberger, on constate que le climat du pays, en général, paraît favorable pour la croissance et 

le développement de cette espèce. Du point de vue pluviométrique, à l‘exception des zones 

sahariennes, les précipitations sont assez abondantes et ne constituent pas un facteur limitant. Du 

point de vue des températures, l‘étude a prouvé la capacité de la plante à germiner entre 8 þC et 

35þC. En fonction des régions, des températures similaires se présentent tout au long de l‘année 

sur la zone côtière et durant le printemps et l‘été sur la zone continentale. 

Les potentiels hydriques qui ont été testés sont compris entre l‘humidité au point de 

flétrissement et ‘humidité à la capacité au champ c‘est à dire l'eau occupe alors ce qu'on appelle 

la microporosité et ne circule plus que très lentement et le sol ne se dessèche que par évaporation 

directe pour les couches les plus superficielles. Mais le plus remarquable est le fait que les degrés 

d‘humidité enregistrés a niveau de -1,3 MPa sont très proches de l‘humidité au point de 

flétrissement, pour chaque type de sol. Ceci met en valeur la capacité de V. enceloides à germer 

dans des situations hydriques très difficiles et sa tolérance au stress hydrique. 

De point de vue texture, Al Faraj & al. (1988) et Kaul et Mangal (1987) confirment que 

V. enceloides préfère les sols sablonneux, et l‘importance de la germination diminue avec 

l‘augmentation de la fraction argileuse dans le sol. 



165

Références 

Al Faraj & MM, Hassan HM & Al Dosoky RA (1988) Germination studies on Verbesina enceloides (Cav.) Benth. 

Et Hook. Ex A. Gray (Astercaeae). Journal of Arid environments 15, 169-174. 

Ameur A & Bouhache M (1994) Projet Morelle Jaune (Solanum elaeagnifolium Cav.). Synthèse des travaux 

effectués au Maroc. IAV Hassan II, INRA et DERDA. 141 p. 

Baker DC, Keeler RF, & Panter KE (1992) Concentration of Galigine in Verbesina encelioides and Galega 

oficinalis and the Toxic and Pathologic Effects Induced by the Plants. Journal of Environmental Pathology, 

Toxicology and Oncology 11(2), 11-17. 

Bautista RC & Mau R FL (1994) Preferences and development of western flowers thrips on plant hosts of tomato 

spotted wilt tospovirus. Environmental Pathology 23, 6 

Bautista RC & Mau RFL, Cho JJ & Custer DM (1995) Potential of tomato spotted wilt tospovirus plant hosts in 

Hawaii as virus reservoirs for transmission by Franfliniella occidentalis (Thysanoptera: Thripidae). 

Phytopathology. St. Paul, Minn.: American Phytopathological Society Vol. 85 9, 953-958. 

Campero CM, Caracino M, Chayer R, Cosentino B & Lopez TA (1996) Experimental Toxicity of Verbesina 

encelioides in Sheep and Isolation of Galegine. Vet. Human Toxicol. 38(6), 417-419. 

Cho JJ, Mitchell WC, Tabashnik BE & Yudin LS (1988) Colonization of Weeds and Lettuce by Thrips 

(Thysanoptera: Thripidae). Environmental Entomology 17(3), 522-526. 

Forrest LM & Smith JW, JR (1996) Influence of Verbesina encelioides (Asteraceae) on Thrips (Thysanoptera: 

Terebrantia) Populations and Tomato Spotted Wilt Virus Epidemics in South Texas Peanut Fiels. Journal of 

Economic Entomology 89(6): 1593-1600. 

Grichar WJ & Sestak DC (1998) Control of Golden Crownbeard (Verbesina encelioides) in Peanut (Arachis 

hypogea) with Postemergence herbicides. Peanut Science 25, 39 – 43. 

Jahandiez E & Maire R (1931-1934) Catalogue des plantes du Maroc, 3 tomes, éd. Lechevallier, Paris, 913 p. 

Kaul MLH & Mangal PD (1987) Phenology and germination of Crownbeard (Verbesina encelioides). Weed Science 

35, 513-518. 

Keeler RF, Baker DC & Panter KE (1992) Concentration of galegine in Verbesina encelioides and Galegia 

officinalis and the toxic pathological effects induced by the plants. Journal of Environmental Pathology 11, 

275-81. 

Lopez TA, Campero CM, Chayer R, Cosentino B & Caracino M (1996) Experimantal toxicity of Verbesina 

encelioides in sheep and isolation of galegine. Vet. Hum. Toxicol. Manhatan, Kan.: Kansas States University, 

Vol. 38 6, 417-419. 

Mitchell FL & Smith JW Jr (1996) Influence of Verbesina encelioides (Asterales, Asteraceae) on thrips 

(Thysanoptera: terebrantia) population and tomato spotted wilt virus epidemics in south Texas peanut fields. 

Journ. Econ. Entomol. Lanham, Md.: Entomological Society of America Vol. 89 6, 1593-1600. 

Qorchi M & Taleb A (1997) Situation Actuelle de l'infestation par la Morelle Jaune dans les Différents Périmètres 

Irrigués du Maroc. Journée nationale sur la morelle jaune: Ampleur du problème et stratégie de lutte, pp 5- 

8. 

Tuvia Y (1998) The dispersion of the invasive weeds Heterotheca subaxillaris and Verbesina encelioieds in Israel. 

6 th EWRS Mediterranean Symposium, Montpellier, pp. 56-57. 

Usha G (1987) Allelopathic Effects of Verbesina encelioides Cav.. Annals of Arid Zone 26(4), 287-291. 

Taleb A & Bouhache M (2005). Etat actuel de nos connaissances sur les plantes envahissantes au Maroc. 

International Workshop "Invasive Plants in the Mediterranean Type Regions of the World" - 25-27 May 2005 

in Montpellier; France 

Tanji A & Taleb A (1997) A newly species recently introduced into Morocco. Weed Research 37, 27-31. 

D‘Alleizette Ch (1919) Note sur une compose nouvelle pour la flore d‘Algérie, Verbesina enceloides Bent & Hook 

(Ximenesia enceloides Cavan.). Bull. Soc. Hist. Nat. Afrique du Nord, Alger. 

Yessef M (1984) Contribution à l'étude de l'installation et de la survie de l'armoise blanche (Artemisia herba alba 

Asso). Germination, développement des plantules et survie des différentes catégories d'individus. Mémoire 

de 3 ième cycle Agronomie I. A. V. Hassan II Rabat. 



166

New species threatening the biodiversity in Morocco: Verbesina encelioides (Asteraceae) 

Verbesina encelioides (Cav.) Benth. et Hook. ex Gray is an invasive alien weed recently 

introduced in Morocco. It invaded completely the perimeter of Souss–Massa (region of Agadir). 

From there it was disseminated towards other areas: Safi, Rabat, Larache, Fez, Sefrou, etc. This 

study was conducted in order to evaluate the infestation area, describe the morphological and 

ecological characteristics of V. encelioides, to point out threats of this species, on one hand, and 

to study the effect of certain environmental factors on its seeds germination (temperature, 

photoperiod, water stress and burial depth) on the other hand. The surveys pointed out the 

importance of its presence in areas more or less disturbed by man and the fact it attracts the 

white fly. 

The viability test of seeds revealed an average of 92% of viable akenes. The kinetics of 

imbibition was fast during the first 12 hours of incubation and it was slowed down beyond that. 

The tests of germination showed the capacity of the akenes to germinate in a temperature range 

of 8þC to 35þC with an optimum at 15þC/25þC, light and dark. Also, a reduction of water 

potential until -0,6 MPa did not affect germinative capacity of the akenes. However, the 

reduction of the water potential from –0.6 MPa to –1.3 MPa reduced the percentage of 

germination. The emergence seedlings occurred up to 3.5 cm of depth. The maximum of 

emergences was recorded at 1.5 cm followed by 0 and 2.5 cm and then 3.5 cm burial depth. 

Beyond 7 cm burial depth, the emergence did not occur. Regarding the growth and development, 

V. encelioides achieve life cycle (from emergence to the maturity of first akenes) in 80 days. It 

allocated more biomass to stems and branches and then inflorescences (starting from the 

flowering stage). Seed production was abundant and continuous for as long growing conditions 

permit. 



167

Stages in the Development of an Early Detection and Rapid Response (EDRR) Program for 

Invasive Alien Plants in California 

Kassim Al-Khatib and Joseph M. DiTomaso 

University of California, Davis. USA, E-mail: Kalkhatib@ucdavis.edu 

Introduction 

To develop an effective Early Detection and Rapid Response (EDRR) 

program, several factors need to be considered. Initially, a comprehensive list 

of current and potentially invasive alien species needs to be established in the 

region of interest. The California Invasive Species Advisory Committee 

recently developed such a list for invasive alien plants and other invasive taxa. 

Secondarily, a system must be established to rapidly and accurately identify 

new invasive alien plants within an area. A third important phase of an EDRR 

program is the ability to predict the potential range of invasive alien plants. 

This can be accomplished by climate matching models. Preliminary work by 

the California Invasive Plant Council (Cal-IPC) mapped the distribution of 36 

of the top 200 invasive alien species in the state. Using the climate matching 

program CLIMEX, they determined the potential suitable range under current 

and climate change conditions (+3 o C). The fourth phase in the establishment 

of an EDRR program requires a thorough understanding of the control methods 

that can effectively eradicate new incipient infestations. To achieve this, 

several groups in California have been working to develop appropriate 

management strategies, including Cal-IPC, the California Department of Food 

and Agriculture, the University of California (UC) Cooperative Extension, and 

members of the state Weed Management Areas. Much of this information is 

available on three primary websites associated with Cal-IPC, the UC Weed 

Research and Information Center, and the UC IPM program. Eventually, 

management options will be linked to the online diagnostic identification tool. 

Finally, a funding system must be in place to allow rapid response to new 

potentially damaging invasive alien plants. Legislative activity at both the state 

and national level are attempting to provide this funding source. While none of 

these phases are yet completed in California, all are now underway and may 

eventually lead to an effective EDRR program. 

The annual cost of losses and environmental damage due to invasive alien species in the 

United States has been estimated to be $120 billion (Pimentel et al. 2005). Invasive alien plants 

alone cause an estimated $35 billion in losses, damages, or control costs including $27B for crop 

weeds, $6B for weeds in pasture, $1.5B from weed in lawns, gardens, and golf courses, and the 

remaining for aquatic weeds and melaleuca. The high cost of invasive alien species is, in part, 

attributed to the lack of an effective means for early detection and control of emerging invasive 

alien species before they are widespread. Therefore, it is critical to develop a systematic 

approach for detection, reporting, rapid risk assessments, and response to new invasive alien 

plants. Early Detection and Rapid Response (EDRR) of invasive alien plants and other 

168 



organisms is a management approach that focuses on surveying and monitoring at-risk areas to 

find infestations at their earliest stages of invasion. Along with prevention, this method is the 

most successful and cost effective means of control. 

In the United States, several federal and state agencies have historically cooperated to 

encourage invasive alien plants prevention. These agencies included U.S. Geological Survey 

(USGC), United States Department of Agriculture Animal and Plant Health Inspection Service 

(USDA APHIS), state departments of agriculture, and University Cooperative Extension 

services. The first attempt to develop a National EDRR Plan started in 2000 when a planning 

workshop was hosted by USGS and USDA. Immediately following the workshop, the first 

regional Invasive Plant Atlas for the northeast was published. A USDA-APHIS conceptual 

design plan for the National EDRR System was developed in 2003. Over the past ten years, most 

of the States have developed Invasive Species Councils, and advisory committees. Progress in 

addressing new invasive alien plants is being made by a number of task forces. 

Additionally, the National Plant Diagnostic Network (NPDN) was established to coordinate 

land grant institutions, national agencies and state departments of agriculture efforts in data 

gathering, diagnostic collaboration, and other activities of plant diagnostics. NPDN consists of 

five regional plant diagnostic centers located at Cornell University (NEPDN); Michigan State 

University (NCPDN); Kansas State University (GPDN); University of Florida (SPDN); and 

University of California, Davis (WPDN). NPDN uses a common software interface to process 

diagnostic requests and share information among diagnostic laboratories. 

In California, there is a great concern about introducing invasive alien plants that may damage 

ecosystem processes such as community diversity, hydrology, fire regimes, and soil chemistry. 

Research has shown that invasive alien plants have a competitive advantage because they are no 

longer controlled by their natural predators or pathogens, and can quickly spread out of control. 

The concern about invasive alien species in California is ubiquitous because the state shares a 

long border with other States and neighbors Mexico where invasive alien plants may be 

established there before entering California, and also has three major sea ports and several 

international airports. In addition, California has the largest nursery and seeds industry in the 

country that may facilitate the introduction of many new plants. In California, approximately 

20% of the plant species established and growing under natural or non-cultivated conditions are 

non-native, with 3% considered harmful invasive alien plants (DiTomaso and Healy, 2007). 

Although the percentage is small, these invasive alien plants inhabit a large proportion of the 

landscape. 

Early eradication of invasive alien species is the most cost-effective approach for the 

economic welfare of California, the United States, and other counties around the world. By 

comparison, once an invasive alien species becomes widespread, eradication is almost never 

economically feasible (Rejmanek & Pitcairn 2002). While management of well established 

invasive alien plants in California is important, it is equally critical to protect natural areas yet 

uninfested. 



169

California Early Detection and Rapid Response Program 

Invasive alien plants inventory 

Generating a list of invasive alien species provides a foundation for setting strategic priorities 

and resource management. Three lists of invasive alien species were developed in California. 

The oldest list, which is the only one with legal authority, was developed by California 

Department of Food and Agriculture (CDFA). The CDFA Noxious Weed List was developed to 

address the obligations of the Department to protect the state‘s agricultural industry and prevent 

the introduction and spread of injurious plant pests. Plant species that have been designated as 

noxious weeds are subject to various restrictions including the statutory provisions for weed-free 

areas, noxious weed control, prohibitive interstate transport, and provisions of the California 

Seed Law. Management or control activities taken against noxious weeds may both protect 

California's agricultural industry and important native plant species. CFDA Noxious Weed List 

includes 180 species, most of them of agricultural importance. The list has been revised over the 

years; however, the process is relatively slow and may not serve EDRR objectives. 

CDFA list of noxious weeds are classified into five categories (CDFA, 2010). Category ―A‖ 

Noxious Weeds include plants (62 species) of expected economic or environmental damage and 

are present in limited distribution within the state. These species are often targeted for 

eradication. Approximately 16 A-rated plant species have been successfully eradicated in recent 

years. A-rated species and their reproductive parts are legally prohibited from entering the state. 

Category ―B‖ Noxious Weeds include plants (84 species) with known economic or 

environmental detriment and are considered regionally widespread, but are not present in many 

areas of the state. Eradication, containment, suppression, control, or other holding action is at 

the discretion of the individual county agricultural commissioner. Category "C" Noxious Weeds 

include plants (30 species) of known economic or environmental detriment and are generally 

widespread in the state. They are subject to regulations designed to reduce spread, but little 

funding is provided for their control, except when they are the target of biological control efforts. 

Category "Q" Noxious Weeds include plants (3 species) that are not present in the state and 

agricultural or environmental damage is suspected or known to occur elsewhere. These species 

are typically new to the state and can be treated as A-rated plants. Such species can be the prime 

target of an EDRR program. Category "H" plants (1 species) are potentially invasive alien plants 

derived from nursery grown material. 

The second list of invasive alien plants in the state was developed by the California Invasive 

Plant Council (Cal-IPC). The list is focused on plants with potential to cause significant 

ecological damage in natural areas, including displacing native plants and wildlife, increasing 

wildfire and flood danger, consuming valuable water, degrading recreational opportunities, and 

destroying productive range and timber lands. The majority of plants on this list do not infest 

row-crop agricultural systems. While the Cal-IPC list is based on a transparent and published set 

of criteria, it does not have any regulatory authority within the state. However, local authorities 

in California often use the list to regulate plant introduction and landscape plantings. 



170

The objectives of the Cal-IPC plant inventory are to provide a uniform methodology for 

categorizing non-native invasive alien plants that threaten wildlands; provide a clear explanation 

of the process used to evaluate and categorize plants; provide flexibility so the criteria can be 

adapted to the particular needs of different regions and states. The system generates a plant's 

overall rating based on an evaluation of 13 criteria, which are divided into three sections 

assessing Ecological Impacts, Invasive Potential, and Ecological Distribution (Cal-IPC, 2010). 

Evaluators assign a score of A (severe) to D (no impact) for each criterion, with U indicating 

unknown. Based on this scorecard, invasive alien plants were grouped in three categories, High 

(plants with severe ecological impact), Moderate (plants with substantial and apparent ecological 

impacts), and Limited (plants whose ecological impacts are either minor or are very limited in 

range). In total, the Cal-IPC list includes about 205 plants. 

The newly established California Invasive Species Advisory Committee (CISAC) has recently 

developed a comprehensive list of species that have a reasonable likelihood of entering or have 

entered California for which an exclusion, detection, eradication, control or management action 

by the State might be taken. The list included 508 plant species with 320, 96, and 92 

herbaceous, grass, and woody species, respectively. Among these species only 98 species are 

included as highest priority species, when evaluated for their spread rate and ecological, 

agricultural, structural, and health damage/benefit (CISAC, 2010). Unlike the CDFA list, this list 

is based on clearly defined and transparent criteria. While the criteria are similar to the Cal-IPC 

list, the CISAC list includes invasive alien species of both agricultural and non-agricultural 

areas. However, like the Cal-IPC list, it does not yet have any legal authority. 

While California has develop excellent lists of invasive alien plants, the next critical step in 

the process is to provide a single list of priority species of both agricultural and natural areas that 

has regulatory authority within the state. Because of the legal authority of CDFA, the list should 

be housed and maintained by CDFA. Such a comprehensive and centralized list that increases 

the knowledge base of target organisms, including economic and ecological impacts is the first 

step in an effective EDRR program. 

Invasive alien plant diagnostics 

Several universities, state and federal herbaria have historically provided an excellent 

resource for the identification of both native and non-native plants in California. The collection 

and diagnostic capabilities of the University of California, Davis, and CDFA, in particular, have 

specialized in invasive alien plant identification, and both have extensive herbarium collections 

on non-native species. In addition, the flora of California (Hickman, 1993) is an excellent 

resource and a revised edition is already online (http://ucjeps.berkeley.edu/jepsonmanual 

/review/), with a hard copy expected to be published within the next couple of years. There are 

also a number of local floras in the state that can be of great assistance in plant identification. 

In addition to these well established diagnostic facilities and resources, California has the 

most comprehensive weed identification manual (DiTomaso & Healy 2007) developed for any 

state within the United States. The book includes over 3000 color photographs and descriptions 

for over 750 weed species, including agricultural weeds, nearly all of the invasive alien plants 



171

included in the Cal-IPC inventory, the noxious weeds on the CDFA list, and the invasive alien 

plants listed by CISAC. 

Although these resources are readily available for professionals working in the field, they are 

encyclopedic or require considerable training to use and, thus, play a limited role in training 

volunteer groups and many other land managers not adept in plant identification. However, the 

effectiveness of an EDRR program depends heavily on volunteer groups and organizations, as 

well as a wide variety of field practitioners. Furthermore, the critical identification timing for 

effective eradication or management of an incipient invasive alien population is before flower 

and seed production, when plants are immature. Most dichotomous keys found in floras rely on 

flowers and mature plant characteristics for identification. Furthermore, color photographs found 

in guidebooks are often of flowering plants. To increase the ability of individuals to identify 

invasive alien plants at all stages of development, an interactive identification program was 

developed in California and is available on compact discs (http://calweeds.com). This software 

program allows for selection of over 200 characteristics of a plant, including many vegetation 

features. The program narrows the choices down with every characteristic selected until one or a 

few choices remain. Photos and descriptions can then be used to determine the correct species. 

The advantage of this approach is that it allows for identification of seedlings and immature 

plants. However, this tool also requires some knowledge of plant morphology. Another recently 

developed online resource is a much simpler interactive web-based tool (http://wric.ucdavis.edu). 

This tool can be custom developed to include any group of plants of interest, including only 

invasive alien species. The website was developed for use by individuals with little training in 

plant identification and can be used to train volunteers on invasive alien plant identification. The 

tool can also be used on Smart Phones. Furthermore, new innovative technology is becoming 

available that allows entry of new species of invasive alien plants with photo verification using 

Smart Phone technology. 

With all the key tools already available to accurately identify invasive alien species, the last 

critical step is to develop a centralized system that combines field identification, verification, 

data entry, and data retrieval. Such a system is critical in the development of an effective EDRR 

system. In California, this centralized location is best housed in a university environment, 

primarily because of the extensive Information Technology (IT) expertise found in these 

institutions, as well as the extensive herbarium facilities used to identify and house archival 

collections. 

Predictive range expansion 

The third important phase of an EDRR program is the ability to predict the potential range of 

invasive alien plants, and thus, determine where these plants are likely to invade. This can be 

accomplished by climate matching models. While Mapping the risk based on climate maching 

models give useful information, such model cannot correctly predict all the area at risk 

(Gallagher et al. 2010). The University of California at Davis has worked in partnership with 

Cal-IPC to develop an innovative ―risk mapping‖ approach for invasive alien plants. The maps 

generated from this pilot project compare the current distribution of 36 invasive alien plants in 

California with their potential distribution based on the climate matching model CLIMEX. The 

approach combined two types of data into a GIS map, including expert opinions on current 

172 



distribution and invasion trends (increasing or decreasing), and CLIMEX modeling based on 

each plants global range. 

Hall (2006) and Steinmaus (2002) included data from 321 weather stations in California. This 

greatly increased the spatial resolution of the CLIMEX model. This spatial data provides 

baseline information for the regions of the state where each of the 36 species is expected to 

expand, based on the climate conditions currently present in the state. Such maps provide a more 

efficient method for selecting early detection priority species in any particular region in the state. 

In addition, using the average estimate of temperature increase in California (+3 o C), additional 

maps can be developed to predict the potential range under a climate change scenario. 

Similar maps should be developed for all invasive alien plants in the state and for invasive 

alien plants anticipated to invade California. This information can be linked to an online 

interactive program that would allow land managers or agencies to predict invasive alien plants 

likely to invade a particular area and habitat. These specific ―Watch Lists‖ would be far more 

efficient in training programs for volunteers or those not completely familiar with the California 

flora. 

Invasive alien plant management 

The final phase in the establishment of an EDRR program requires a thorough understanding 

and adoption of methods that can effectively prevent, eradicate, or control new incipient or 

established infestations, as well as providing a clearinghouse for the dissemination of this 

information. Another key element to a successful EDRR program is good coordination between 

federal agencies/regulators as well as states, local entities, industry and other interested parties. 

To initiate an effective management program, it is first necessary to develop a statewide 

strategic plan. While California developed a strategic plan for invasive alien plants in 2005 

(Schoenig, 2005), this plan is currently being expanded by CISAC to include all taxa in a more 

unified approach. Within the plan, it is important to include a strong prevention strategy. 

Prevention is the most cost-effective method of invasive alien plant management and is the first 

line of defense against the spread of invasive alien species. Once introduced, the spread of new 

localized populations of invaders should be considered for eradication. Eradication efforts on 

small populations are far more cost effective compared to populations that have spread to large 

area (Rejmanek & pitcaim, 2002).To be successful, it is essential that invaders be detected at 

early establishment stages through a well developed EDRR program. 

Integrated Pest Management (IPM) should be considered a guiding principle to any 

management program (Flint & Gouvelia, 2001). An IPM approach should be used when 

invaders are well established and widespread. IPM is a science-based decision-making process 

that reduces risks from pests and pest management strategies. It includes coordinating the use of 

pest biology, environmental information, and available technology to prevent unacceptable 

levels of pest damage by the most economical means while posing the least possible risk. Several 

complementary methods may be implemented in an overall IPM strategy to protect ecosystems 

and aid in their recovery. 

There are several groups in California that have been working to develop appropriate 

management strategies and educational outreach and training materials for invasive alien plants 

173 



over the years. These include scientists and researchers associated with Cal-IPC, CDFA, 

University of California (UC) Cooperative Extension, Weed Management Areas, and private 

entities. Through these efforts, there are many examples of successful control strategies for 

specific species and ecosystems. Much of this information is available on three primary websites 

associated with Cal-IPC (http://cal-ipc.org), UC Weed Research and Information Center 

(http://wric.ucdavis.edu), and the UC IPM program (http://www.ipm.ucdavis.edu/). 

As the final step in an effective EDRR program, two additional aspects are required. First, an 

online clearinghouse for information on prevention strategies, methods to prioritize eradication 

efforts, management options, and follow-up monitoring programs are necessary. This 

information should be linked to the invasive alien plant inventory, online diagnostic 

identification tools, and the predictive range expansion program. This would allow volunteers 

and land managers to anticipate species that are likely to invade particular areas, rapidly identify 

new incipient populations, and response quickly with eradicate or containment efforts when 

these populations are discovered. To be successful, however, a funding system must be in place 

to allow rapid response to new potentially damaging invasive alien plants. Legislative activity at 

both the state and national level are attempting to provide this funding source. While none of 

these phases are yet completed in California, all are now underway and may eventually lead to 

an effective EDRR program. 

References 

Bossard CC, Brooks ML, DiTomaso JM, Randall JM, Roye CL, Sigg J, Stanton AE & Warner PJ (2006) California 

Invasive Plant Inventory. California Invasive Plant Council, Publ. #2006-02. Berkeley, CA. 39 pp. 

CA-IPC, California Invasive Plant Council (2010) Invasive Plant Inventory. http://www.calipc.org/ip/inventory/index.php. 

CDFA, California Department of Food and Agriculture (2010) Weed List-Pest Ratings of Noxious Weed Species. 

http://www.extendinc.com/weedfreefeed/list-b.htm. 

CISAC, California Invasive Species Advisory Committee (2010) The California Invasive Species List. 

http://www.iscc.ca.gov/species.html. 

DiTomaso JM & Healy EA (2007) Weeds of California and Other Western States. Univ.Calif. Div. Ag. Nat. Res. 

Publ. 3488. 1809 pp. 

Flint ML & Gouvelia P (2001) IPM in Practices: Principle and Methods of Integrated Pest Management. 2001. 

University of California ANR Publication 3418. Oakland, CA. 

Gallagher RV, Beaumont LJ, Hughes L & Leishman MR (2010) Evidence for climatic niche and biome shifts 

between native and novel ranges in plant species introduced to Australia. J. Ecology 98, 790-799. 

Hall J (2006) Modeling climatic preferences of an invasive woody shrub, Ulex europaeus L., and a biological 

control agent, Tetranychus lintearius Dufour, in California. M.S. Thesis. Cal-Poly-San Luis Obispo, San Luis 

Obispo, CA. 

Hickman JC (ed.) (1993) The Jepson Manual: Higher Plants of California. Univ. Calif. Press. 1400 pp. 

Ielmini M & Ramos G (2003) A National Early Detection and Rapid Response System for Invasive Plants in the 

United States. http://www.fws.gov/ficmnew/FICMNEW_EDRR_FINAL.pdf 

Pimentel D, Zuniga R & Morrison D (2005) Update on the environmental and economic costs associated with alieninvasive 

species in the United States. Ecological Economics 52, 273-288. 

Rejmanek M & Pitcairn MJ (2002) When is eradication of exotic pest plants a realistic goal? 

In C. R. Veitch, M. N. Clout, [eds.]. Turning the tide: the eradication of invasive species, 249-253. International 

Union for the Conservation of Nature and Natural Resources, Gland, Switzerland. 

Schoenig S (2005) California Noxious and Invasive Weed Action Plan. CDFA, 45 pp. 

Steinmaus S (2002) Predicting Plant Invasion with Modeling. CalEPPC News. 1, 5-9. 

Warner PJ, Bossard CC, Brooks ML, DiTomaso JM, Hall JA, Howald AM, Johnson DW, Randall JM, Roye CL & 

Stanton AE (2003) Criteria for Categorizing Invasive Non-native Plants that Threaten Wildlands. California 

Exotic Pest Plant Council and Southwest Vegetation Management Association. http://www.calipc.org/ip/inventory/pdf/Criteria.pdf. 



174

Early experiences in the establishment of a National Early Detection and Rapid Response 

Programme for South Africa 

Philip Ivey 1 , John Wilson 1,2 , Ingrid Nänni 1 and Hilary Geber 3 

1 

Early Detection and Rapid Response Programme for Invasive Alien Plants, South African 

National Biodiversity Institute, Kirstenbosch National Botanical Gardens, Claremont 7735, 

South Africa. E-mail: P.Ivey@sanbi.org.za 

2 


Matieland 7602, South Africa 

3 

Centre for Learning, Teaching and Development, University of the Witwatersrand, 1 Jan Smuts 

Avenue, Braamfontein 2000, Johannesburg, South Africa 

Background 

The Working for Water Programme is an initiative of the South African 

Government to manage invasive alien plants through job creation in a country 

with chronic unemployment. It provides opportunities for people to learn new 

skills, gain self-confidence, at the same time as reducing threats to the country's 

natural resources. To date, most of the work has focussed on area-specific 

clearing operations, but in 2008 a National Early Detection and Rapid 

Response (EDRR) Programme for Invasive Alien Plants was established. As of 

2010, the Working for Water programme in South Africa has devoted 1.43% of 

its budget of seven hundred million Rand (€63,000,000, July 2010) to EDRR. 

This paper will explore the challenges and opportunities of setting up such a 

programme in the context of the job creation goals of Working for Water and 

the unique challenges of South Africa. In particular we discuss monitoring 

approaches, which species to target, engagement of stakeholders, staffing 

issues, a programme designed to provide mentorship for staff, institutional 

arrangements, and how political pressures have affected the operation. We 

conclude that the EDRR programme is an important new addition to invasive 

alien plant management in South Africa, and that, to be most effective, the 

programme should continue with its remit of using stake-holder networks to 

combine early detection with eradication. 

With a budget of seven hundred million Rand (€63,000,000, July 2010) allocated for 

management of invasive alien plants the South African government, through its Working for 

Water (Department of Water Affairs Website) has shown that it takes the threat of invasive alien 

plants to biodiversity, ecosystems, environmental services and human livelihoods seriously. The 

management of invasive alien plants also has benefits in terms of job creation where 

unemployment is high. However, a labour-intensive approach to the management of invasive 

alien species, whilst enjoying relatively well-recognised success, is not necessarily the most cost 

effective way of managing all aspects of the problem. A disproportionately small amount is 

devoted to preventing the arrival of new invasive alien species and even less on detecting the 

early establishment of new alien plant species. Early detection and possible eradication of new 



175

invasive alien plants may be more cost effective if efficient systems of early detection and 

successful eradications are achieved. 

The South African National Biodiversity Institute (SANBI) was formed with the 

promulgation of the National Environmental Management and Biodiversity Act, 2004. SANBI‘s 

mission is ‗To promote the sustainable use, conservation, appreciation and enjoyment of the 

exceptionally rich biodiversity of South Africa, for the benefit of all people’. Among the 

functions of SANBI listed in the Act are that it must monitor and report to the Minister on the 

status of invasive alien species (National Environmental Management and Biodiversity Act 

(NEM:BA), 2004, Chapter 2, Part 1, 11.1.a.iii) and it may co-ordinate and implement 

programmes for the prevention, control or eradication of listed invasive alien species (NEM:BA, 

2004, Chapter 2, Part 1, 11.1.m.ii). The draft regulations (section 9.4.f) pertaining to this Act 

state that SANBI should collate information on invasive alien species management programmes 

including: "research into any aspect of the invasiveness of an alien or listed invasive species or 

the prevention, eradication or control of such invasiveness". 

In March 2008 SANBI was contracted by the Working for Water Programme of the 

Department of Water Affairs to develop, in partnership with other stakeholders, a programme of 

Early Detection and Rapid Response (EDRR) for Invasive Alien Plants. In this paper we will 

describe how the initial strategic plan was formulated, the current focus of efforts, and some of 

the challenges faced. 

Development of a Strategic plan 

In February and March 2008 a range of stakeholders from relevant government departments, 

scientific institutions and non-governmental organisations were consulted on the role EDRR 

should take. They were keen to see a practical, not overly ambitious programme that would make 

a real difference in reducing the likelihood of new plant invasions. The strategic plan outlined 

four key areas of implementation, 

1. Early detection, 

2. Identification and verification, 

3. Risk assessment and response planning, 

4. Rapid response, 

and specified that these should be supported by the following services: good information 

management, advocacy and awareness raising, and research. At this early stage of strategic 

planning a possible stumbling block emerged as although SANBI is clearly mandated to work on 

the first three key areas, it did not feel it had a definite remit to carry out actual implementation 

of rapid response to eradicate or control invasive alien plant outbreaks. The EDRR programme 

and work plan were influenced by this lack of clarity regarding rapid response roles. 

Stakeholders also emphasized the need for a co-ordination of effort as much work has already 

been done by key stakeholders such as the Department of Agriculture, the Agricultural Research 

Council, Universities, and the Council for Scientific and Industrial Research. SANBI was 

encouraged to work in partnership to ensure that efforts were not duplicated and limited 



176

esources were not wasted. In particular, many databases and systems were already in place for 

managing knowledge and information on invasive alien species. 

The final strategic plan proposed a national co-ordination unit that would work with a number 

of regional co-ordination units to direct the efforts of volunteer invasive alien plant ‗spotters‘. 

Each regional unit would develop a regional list of species to be monitored, and conduct more 

general monitoring at key sites. The vision was that when spotters detected a new invasive alien 

plant, the regional co-ordinators would be contacted, and the regional co-ordinator would 

employ taxonomists at SANBI Herbaria to verify the identity of the plant. The risk posed by 

each new incursion was then to be assessed by a to-be-formed Invasive Plant Assessment Panel, 

which in turn would make recommendations as to the appropriate response. Regional Rapid 

Response teams would then be responsible for executing and reporting the outcome of their 

actions. To a greater or lesser extent each of these aspects have been explored and developed 

during the first year and a half of operation. The degree of successful achievement still needs to 

be assessed and changes need to be recommended and implemented given our revised 

understanding of the situation. In particular, the programme is adopting a more proactive model 

than the linear model described above (see Fig. 2 below). 

The stated mission of the Early Detection and Rapid Response Programme is to protect 

ecosystem services from the negative impact of invasive plants through surveillance that enables 

early detection of invasions and allows for appropriate action. 

The programme, in accordance with applicable legislation and the needs of stakeholders, aims to 

achieve the following objectives: 

1. Co-ordinate surveillance through an early detection programme for emerging invasive alien 

plants. 

2. Develop capacity and systems to allow for rapid and accurate identification and verification 

species detected by the surveillance teams. 

3. Ensure optimum institutional co-operation to facilitate risk assessment of emerging invasive 

alien plants in South Africa. 

4. Co-ordinate the organization of rapid response teams to respond when invasions have been 

detected and the course of action decided and approved. 

5. Develop and co-ordinate effective information management systems that allow for readily 

accessible, rapid and accurate exchange of information between all those involved in the 

programme and also to provide appropriate information to wider audiences. 

6. Initiate and execute relevant research on early detection, risk assessment and rapid response 

aimed at continuously improving the programme. 

7. Plan and implement an advocacy and awareness raising programme to elevate the profile of 

the early detection programme and the issue of invasive alien plants. 



177

8. Design and implement a monitoring and evaluation programme to assess effectiveness of the 

above programmes and to recommend improvements. 

9. If appropriate, plan for SANBI to take full control of the programme and ensure permanent 

financial support from the South African Government Treasury. 

Objectives one to four include the key implementation areas of the whole programme. 

Objectives five, six and seven support the programme and are essential for the successful 

achievement of the first four objectives. Objectives eight and nine will ensure the development, 

improvement and longevity of the programme. 

Planned and actual programme activities 

The programme has been going for one and a half years. Thus far the results of the 

programme have been encouraging, but a flexible approach to the problems and situations has 

had to be adopted in order to make progress. Here we discuss the four main planned activities of 

the EDRR, namely early detection of plant invasions, identification and verification of the 

invasive alien species, risk assessment and response planning, and rapid response actions. In 

each case we discuss some of the key factors limiting progress, and potential solutions to them. 

1. Early detection 

Background 

In many respects South Africa already has a system for the detection of invasive alien plants 

in the form of the Southern African Plant Invader Atlas (SAPIA). SAPIA arose from road-side 

survey work initiated in 1979 by Lesley Henderson, and over the past 31 years this atlas project 

has gathered distribution data on invasive alien species across Southern Africa. As at March 

2010, it contains ~70,000 locality records of ~660 naturalized alien plant species in South Africa, 

Swaziland, and Lesotho (Henderson, 2010). The project has utilized the skills and enthusiasm of 

‗volunteer‘ observers who have submitted records to add to the ‗professional‘ collection of 

records carried out by Lesley Henderson, the project co-ordinator, but throughout some form of 

record verification was attempted (be it simply asking for a photograph or a sample if the 

contributor did not have much botanical experience). The importance of the SAPIA database was 

acknowledged at the outset of the EDRR, and stakeholders encouraged the programme to use 

these data as a foundation, and to feed information back into the data-base. 

How was the EDRR programme, in its infancy, to best utilize the SAPIA data? With 660 

species listed on SAPIA, which of these could be considered suitable case studies to prove the 

value of an Early Detection programme? Nel et al. (2004) developed a classification system in 

an attempt to establish priority species and areas for management action. In 2004, 117 of the 

over 500 species on SAPIA were considered to be major and established invasive alien species 

and through using their classification system some 84 were considered "emerging" invasive alien 

species. They concluded that management actions should ―aim to eradicate invasive alien plants 

that are confined to small areas or just beginning to become invasive‖. Although the definition 

"emerging" was not explicitly linked to species that were potential targets for eradication. 



178

Determining which species to work on 

In two provinces of South Africa the Early Detection team utilized the SAPIA data to develop 

a list of species to be considered by stakeholders in order to assist with priority setting. Species 

that occurred in 10 quarter degree squares or fewer in the provinces of KwaZulu-Natal and 

Western Cape were arbitrarily deemed "emerging" invasive alien plants, again the phrase was 

not explicitly linked to potentially management options or legislation. At a workshop in 

KwaZulu-Natal in March 2009 a great diversity of opinion emerged about what species should 

be on the list. It was resolved that further criteria be developed to assess the species and to set 

the order of priorities for action. In July 2009 at a workshop in the Western Cape the 

stakeholders were asked to consider a similar list of species for the winter rainfall region. 

However stakeholders recommended that the team focus on a few case studies that showed 

promise of being able to generate results quickly (i.e. "low-hanging fruit") to prove the value of 

EDRR. 

The case studies currently being investigated by the EDRR team are listed in Appendix. 

Developing networks 

During the planning of the EDRR Programme it was recognized as essential to incorporate 

local knowledge of invasive alien species and environments, and that a broad range of people 

should be encouraged to report early signs of new invasions. Based on the experiences of 

SAPIA, there are probably 30–40 highly knowledgeable, enthusiastic, and dedicated people in 

South Africa with field experience who are able to ‗spot‘ invasive plants amongst the 22 000 

indigenous and 8 000 exotic species in the country. There are many more potential observers 

who spend time observing the vegetation they walk and work in and who can determine changes 

in plant communities and, if trained, identify noticeable plants. For early detection to be 

effective, clearly both groups needed to be utilised. 

Regional co-ordinators have encouraged support for the programme from people with strong 

local knowledge, e.g. farmers involved in stewardship programmes, mountain club members, 

Botanical Society Members, and professional botanists engaged in field work. Regional coordinators 

have also met with a wide range of stakeholders and have begun to establish networks 

of ‗spotters‘. 

Wittenberg & Cock (2001) suggest general surveys, site-specific surveys, and species-specific 

surveys as three main ways to achieve the early detection of invasive alien species. At present 

the general surveys are essentially those conducted by SAPIA, and the links to the plant spotter 

network. In terms of site-specific surveys, the regional teams, through their work on case studies 

and in response to calls from observers, have identified a number of locations (including 

arboreta, abandoned farm homesteads, land adjacent to plant nurseries, dams and waterways, 

conservation sites, truck stops near to international borders) that need to be monitored regularly 

and form the foundation for future site-specific surveys. Each regional co-ordinator will develop 

a site-specific monitoring plan for their area of responsibility. In terms of species-specific 

surveys, we are currently not looking for specific alien plants that are not yet recorded in South 

Africa, although such a prohibited list is part of the regulations, such focussed surveys are 

perhaps more appropriate for early detection of animals. We do, however, distribute leaflets on 

each species that we are working on to relevant bodies with the aim of identifying any other sites 

of naturalisation or spread. 

179 



Figure 1 - The current spread of the chosen case study species when compared with all the 

species on the SAPIA database. The red histograms indicate species that are currently 

receiving attention by EDRR. The majority of case study species (red) are recorded in SAPIA 

as occurring in one or two quarter degree grid cells in Southern Africa. 

2. Identification and verification 

Accurate identification of invasive alien plants is essential for numerous reasons but 

specifically: 

1. For assessment of invasive potential. If the species is not correctly identified then 

invasive potential cannot be assessed, as invasiveness of the same taxon elsewhere in the 

world is a prime indicator of whether a species is likely to be invasive. 

2. The course of action to take is determined by the species. If the species is not accurately 

identified then action planning is not possible. Appropriate treatment and herbicides 

cannot be considered without good taxonomic information. However, identification to 

genus level may sometimes be sufficient to allow for general action plans to be made (as 

was the case with Melaleuca species discovered in the Western Cape Province). 

3. Legislation cannot be drawn up against the species if it is not correctly identified. 



180

SANBI has three Herbaria: the National Herbarium in Pretoria, the KwaZulu-Natal Herbarium in 

Durban, and the Compton Herbarium in Cape Town. The identity of plant specimens gathered by 

the programme have been confirmed and verified by taxonomists at these herbaria. The 

programme has employed taxonomists and herbarium assistants to co-ordinate the identification 

efforts. However, as a result of limited taxonomic capacity within South Africa two of the six 

taxonomic support posts catered for in the EDRR programme remain unfilled. 

The need for taxonomic expertise has been apparent in some of the case studies. In the case 

of Melaleuca quinquenerva and Melaleuca ericifolia the confirmed identification has been 

slowed as specimens had to be sent to overseas herbaria for accurate identification. 

There is expertise for genetic analysis in South Africa and this was used to accurately identify 

the Anigozanthos species and hybrids of concern in the Kleinmond area (Le Roux et al., 2010), 

but such molecular diagnostics were only investigated because the issue had been previously 

raised by an expert in the group. EDRR will continue to use molecular tools to aid taxonomic 

identification, particularly where issues of hybridisation or polyploidism may occur, but as a 

programme, more emphasis is required on field identification, and formal herbarium 

identification skills. EDRR offers the opportunity to develop taxonomic capacity, and this is 

clearly of potential broad benefit to biodiversity research in South Africa. 

Provide 

information 

to observer 

network to 

maintain 

interest and 

enthusiasm 

2. Identification and 

verification 

• Herbarium taxonomists and 

molecular work 

• Confirm identity of plant 

species 

• Assess presence of hybrids 

or varieties 

1. Co-ordinate Early Detection 

• Establish a network of observers 

• Develop and implement both site specific and species specific 

monitoring plans 

• Detect locations of alien species 

3. Assessment and 

response planning 

• Assessment of current status of 

species and future risks including 

review of potential threats and 

benefits, models to understand 

distribution, population dynamics, 

impact and pathways 

• Hold stakeholder meeting to 

discuss management options 

5. Change legal status of invasive species 

Species too widespread, national management strategy to be compiled outside EDRR 

Figure 2. Schematic representation of current organisation of EDRR programme 



4. Rapid response 

• Initial response to 

prevent further spread 

• Assess the efficacy of 

management options 

through control actions 

• Attempt eradication 

Species eradicated 

181

3. Risk assessment 

In 2010, South Africa has a new National Environmental Management and Biodiversity Act 

(2004) but has not promulgated regulations which allow aspects of this act to be enforced. The 

impasse caused by lack of regulations has had an impact on the programme. Currently invasive 

alien plants are categorised under the Conservation of Agricultural Resources Act using a series 

of questions which roughly equate to a risk assessment but this approach has not been legally 

specified. A new risk assessment framework to be used to assess invasive alien species is yet to 

be drawn up in terms of the act and will only occur once the regulations have been promulgated. 

In the strategic plan it was proposed that an Invasive Plant Assessment Panel be formed with 

permanent representation of the government departments of Agriculture, Water Affairs and 

Environmental Affairs, and co-opted experts from research institutions to evaluate different 

species as appropriate. This panel would make rapid assessments of new incursions and propose 

appropriate plans of action to be undertaken. 

However, it was recognised that the information required to make informed decisions was in 

many cases missing—the infestations detected were sometimes the only record of invasiveness 

world-wide, and the initial reports did not accurately reflect the infestations (Jacobs et al. in these 

proceedings, and Wilson et al ibid). Field-work was essential to adequately determine risk (see 

Jacobs et al. in these proceedings). Therefore, the programme has decided not to worry too much 

about the lack of framework, but to gather valid information in order to enable accurate risk 

assessment to be carried out. Information will be gathered for each species that has been selected 

as a case study. This information will cover taxonomic details, known current distribution in 

South Africa, projected distribution and spread, impacts and benefits, and a short review of the 

relevant literature. 

A clear feed-back between publicity and awareness-raising, implementation, early detection 

and risk assessment has also emerged. For example, in the case of Triplaris americana, a 

horticultural subject introduced into the Durban- eThekwini Municipality, the impact of taking 

action resulted in newspaper coverage and numerous reports of the species in various localities 

were received. The co-ordinator in this case is continuing to monitor the impact of publicity on 

the number of reports of the species. Similarly, after an initial clearing exercise of populations of 

a cholla cactus (Cylindropuntia sp. poss. tunicata or rosea) outside a national park (conservation 

area) and a presentation at a farmers‘ meeting there was a dramatic increase in reports of this 

species. It is now evident that this species was severely under-reported and recorded on SAPIA, 

and as a consequence eradication in the short to medium term does not appear feasible. Only 

after some initial work was a realistic assessment of risk and potentially feasible responses 

possible. 

4. Rapid response planning and implementation 

182 


2 nd Determining institutional responsibility 

Finding the correct institutional arrangement for Rapid Response activities has proved a 

challenge. At the outset SANBI felt that its remit did not include the actual implementation of 

rapid response to eradicate or control invasive alien plant outbreaks. This will need to be the 

responsibility of another entity. While it may not be appropriate for SANBI, a public entity 


tasked with biodiversity research and policy development responsibilities, to actually implement 

activities involving physical and chemical control of invasive alien plants, there is merit in 

SANBI being involved in the full scope of EDRR (i.e. Early Detection, Identification and 

Verification, Risk Assessment, and Rapid Response implementation). This is particular 

important as efforts of rapid response were found to feed-back to detection of new infestations 

and such information can be important for updating risk assessments (Fig. 2). Moreover, a clause 

in the National Environmental Management and Biodiversity Act states that SANBI may coordinate 

and implement programmes for the prevention, control or eradication of listed invasive 

species. This could be interpreted that SANBI is legally mandated to carry out Rapid Response 

activities. 

The initial plan developed in March 2008 suggested that SANBI should not be responsible for 

implementation of Rapid Response activities. By November 2008 it was apparent that for 

effective research to be conducted rapid response activities had to be integrated with early 

detection and risk assessment (e.g. Zenni et al., 2009). The SANBI executive agreed that the 

Early Detection programme could take on discreet Rapid Response work. However, concerns 

regarding SANBI‘s role in management and clearing of invasive alien plants were again raised as 

this is not SANBI‘s core competence and the Working for Water programme did have structures 

in place to carry out this type of work. In November 2009 it was agreed that a national coordination 

unit for Rapid Response activities would be established within the Working for Water 

programme. In May 2010 SANBI was requested to manage greater Rapid Response activities 

with a larger budget. As the programme is maturing, we are recommending that some specific 

and delimited rapid response responsibilities are retained in perpetuity as these are integral to 

EDRR as a process. 

Pompom weed: an exercise in containment 

The case that perhaps has been most important in defining the extent to which EDRR is 

involved in implementation is the case study of Campanuloclinium macrocephalum (Pompom 

Weed). In 2009 Pompom Weed was listed in 93 quarter degree squares across six different 

provinces in South Africa, far more widely than any other targeted species (Table 1 and Figure 

1). Why then, was Pompom Weed considered a good case study for EDRR? 

The Working for Water programme that sponsors the EDRR has as its key focus clearing of 

large woody and water consuming invasive alien plants. This is most efficiently done by clearing 

a range of species from key water catchments and by working on an area basis. Pompom weed, 

an herbaceous perennial, is distributed along roadsides sparsely in five provinces and densely in 

one province (Gauteng). This discontinuous linear distribution required a species-specific 

management approach rather than an area management approach. The EDRR team was 

requested to manage this species as part of the Rapid Response programme as the approach was 

different to that usually followed by Working for Water. This species gave the team an 

opportunity to develop a rapid response methodology that would suit a species-specific 

approach, aimed at species containment. During the first year of operation the team managed 

only one clearing contract in a single province. During the second year of operation the team 

managed 39 clearing contracts in four provinces. The aim of the Pompom Weed management 

programme is to contain the species into a single province whilst options for biological control 

are being investigated. However, the emphasis is strongly on implementing temporary 



183

containment, and as such it is much less clear that it fits within SANBI's mandate. Indeed one of 

the challenges of EDRR will be to develop a process of exiting species that need to come under 

general management operations, and where classical biological control options should be 

explored. We are recommending that in future a separate, but perhaps related, process to EDRR 

be developed for such containment efforts, otherwise the potential for eradication could again be 

overlooked by the continued resources required for containment efforts. 

Building the program 

There were several key challenges for the program, first building human capacity, second 

enabling field-reports to be accurately captured, and third integrating data collection with 

existing databases. The second and third challenges are being addressed through development of 

appropriate and efficient processes. A novel mentoring programme has been used to tackle the 

first challenge of human capital development. 

Mentor programme fostering human capital development 

The first major hurdle for EDRR has been to recruit 21 staff to offices around the country 

within one year. In order to build the capacity of the early-career staff appointed to the project a 

mentor program was implemented by matching ―silverbacks‖ with 30+ years of experience to 

each staff member. 

The training for the mentors and the EDRR team, including the National Co-ordinator and 

administrative staff, was developed around the Transformational model of mentoring (Geber, 

2006). Transformational mentoring involves the establishing of learning alliances for 

professional development and a commitment to social and organisational change (Geber 2003). 

Mentoring with a transformation emphasis is particularly important in mentoring training, where 

mentors guide less experienced colleagues in order to help them achieve requirements for 

educational and organisational change, which is part of the South African national agenda. 

Each member of the team had a mentor who provided 16 hours of mentoring per month. In a 

review of the progress of the mentoring after almost a year, mentors and mentees said they had 

benefitted greatly from their partnerships. 

Mentees expectations of their mentors in achieving their goals included being guided, advised 

and pointed in the right direction. They expected support and to learn to understand the work 

environment. They expected their mentors to share experiences with them but also for the pairs 

to learn together. They expected their mentors to promote the Early Detection programme and 

help with relationship building with others in the field. Most of the mentees‘ expectations were 

met and in many cases exceeded for both their professional and personal growth. 

Mentees reported on specific areas of research where their mentors had helped them with their 

higher degree studies and other research proposals. Mentees commented that having access to the 

mentors‘ networks enabled them to do their research faster and have avenues of which they were 

previously unaware opened for them. They said that their research was more innovative than 

they could have anticipated. This confirms the findings of de Janasz & Sullivan (2004). 



184

Mentees also spoke about how the mentoring had affected other areas of their lives. Several 

mentees have begun to see themselves in a new light, as professionals in an important national 

programme (i.e. no longer simply graduates or postgraduates working for the Early Detection 

programme, but serious players in their field and competent young professionals). 

They said that the connections they had made through their mentors‘ networks had allowed 

them to operate at levels beyond their expectations and to speak to senior officials and CEOs 

much earlier in their careers than they would have otherwise. Nevertheless they could still make 

individual contributions outside SANBI to the wider community. They now have some influence 

in the field because their mentors have expert reputations. Through the mentor programme team 

members have been introduced to wider networks and this has resulted in information being 

shared between co-ordinators and an ever increasing network of volunteer observers. 

The mentees said that the field trips with their mentors were very valuable and necessary and 

that they learnt an enormous amount during the field trips. The field trips were included in the 16 

hours per month which the mentors spent with the mentees and some mentees felt that there was 

not enough time for their other meetings and would have liked more mentoring time in their 

daily work environment as well. 

The investment in the mentoring was higher than many programmes of this nature. This was 

generously funded by The Working for Water Programme of the Department of Water Affairs. 

The money and time spent by mentors meant a rapid capacity development among mentees. This 

is evident in the range of goals and skills they managed to achieve and develop in a relatively 

short time. The programme also built capacity in mentors as, through experience, they learned 

how to do cross cultural mentoring better. The programme provided access to mentoring, 

especially for young black women, that they are unlikely to have accessed without a formal 

programme (Stone, 2005) 

The mentoring programme has spread awareness of the need for such professional 

development in science / biodiversity in South Africa as revealed by the mentor feedback. 

The mentoring of young researchers in the Early Detection programme stands out as a rare 

and exceptional example of good practice in mentoring and the design and implementation of a 

mentoring programme for capacity building of young biodiversity researchers and practitioners. 

Biodiversity programmes in South Africa and worldwide can benefit from such mentoring 

programmes. 

The major disadvantage of using mentors in such a programme is that the goals and methods 

used by the programme have taken much longer to be standardised, with the mentors pulling in 

different directions to where the program as a whole was headed. Certainly such mentorship 

activities while needed at an early stage, are also most disruptive in a new programme where the 

processes and aims are still to be determined. In a more developed programme the expectations 

of the mentors can be set out much more clearly. 



185

Data capturing using Cyber-Tracker technology 

In order to facilitate ease of data capturing amongst volunteer and professional observers 

software is being developed that will allow for ease of identification of the species for which the 

Early Detection team is seeking information. Cyber-Tracker is a world recognised software 

application that melds the technological world of computer software with the ancient skills of 

trackers. The application for the Early Detection programme has been designed to: 

Allow validation of species identification. Electronic Field Guide pages will include images, 

text and known distribution maps of the up to 660 species on the Southern African Plant 

Invader Atlas. 

Provide a number of taxonomic filters. The software will calculate the number of possible 

species after each filter operation, so that the user can skip to a series of photographs and 

plant names at any stage of the identification process. If the user is unable to make a 

definitive identification, the final result will include all the possible species. A photograph 

and herbarium specimens may be used for validation by a taxonomic specialist. 

Contain up to 700 species, with each species containing about five images installed onto a 

high performance microSD card for efficient distribution. 

Automatically capture required Meta data, such as the name of the observer, contact details, 

methods used, etc. Meta data should also include a record of decisions made by the user 

when selecting taxonomic filters. 

Utilize the integrated camera to capture photos attached to GPS position and attribute data. 

Capture GPS timer track data that can be used to create lines and polygons to plot areas of 

alien vegetation infestation. 

Transmit data captured in the field via a Cellular modem to a specified ftp site hosted by 

SANBI. Data transmission should be verified before clearing the data from the Handheld 

Computer. 

Provide an Efficiency Report to show the number of observations, time spent and distance 

covered per day by each field observer. 

Include a real-time GPS navigation map to enable users to find previously recorded alien 

plants for treatment. Include a map maker to produce maps for the Handheld Computer. The 

moving map feature should indicate the position of the user in real time and display the path 

followed, and 

Most importantly the software should be Open Source and free for conservation use 

worldwide. 

This software application is almost fully developed and field testing was carried out during last 

quarter of 2010. 

Conclusion and way forward 

The EDRR work needs to have a clear mandate and link to the legislation. Due to the large 

number of alien plant species that could be considered, it was proposed that species-specific 

activities be restricted to three groups. First, category 1a species as categorized by the National 



186

Environmental Management and Biodiversity Act. These are Invasive species requiring 

compulsory control. Remove and destroy. Any specimens of Category 1a listed species need, by 

law, to be eradicated from the environment. No permits to have these species will be issued. The 

second list is a Species under Surveillance List which currently does not have appropriate legal 

standing but is a list of species that are of concern but which still require a formal assessment 

before any legally-binding categorisation. And the third group are any new records of 

naturalisation. As such EDRR is focussing on species where the possibility of eradication has not 

been ruled out (although this may simply be because of a lack of available information). 

Good progress has been made towards the establishment of a functioning national EDRR. 

However, some early problems and lessons can be summarised as follows: 

a. The high number of invasive alien plant species already in South Africa that could be 

construed as ―emerging‖ invasive aliens made it difficult to know where to start. Initially 

a priority setting process was embarked upon, but stakeholders suggested targeting a few 

―case studies‖ may be a more appropriate way forward. The fact that EDRR has fasttracked 

a few projects has actually been to the benefit of the programme as a whole, as 

already broader lessons are being learnt (e.g. at what point is a desk-top risk assessment 

appropriate). 

b. The case study focus, however, has detracted from the development of regional 

monitoring strategies but it has given guidance as to how these strategies should be 

structured in future. The foundations for a long term programme of EDRR need to be 

strengthened through establishment and implementation of site and species surveys and 

monitoring. 

c. The limited availability of taxonomic skills has meant that not all positions have been 

filled, this needs to be a focus particularly early on in an EDRR programme (Fig. 3). 

d. A delay in starting the programme combined with a restricted funding timeframe created 

pressure to employ capacity as quickly as possible, and led to excess budget available in 

the first six months of the programme. This skewed some decisions (e.g. the staff 

structure), but these are being resolved with time. 

e. There is value in all processes of EDRR being managed by a single entity. Indeed, 

response activities should be an integral part of activities and feed-back into early 

detection and risk assessment (i.e. EDRR should not be a linear or cyclic process but 

more integrative, particularly given the need to act quickly). 

f. The relatively inexperienced team has been supported by very experienced mentors that 

have enabled team members to develop both professionally and personally. And while, 

the mentorship scheme has meant EDRR programme has taken longer to settle on shared 

goals and methodologies, the mentor programme has given the team members guidance 

and support which has contributed to good retention of staff. 



187

In the future we anticipate the workloads in the four different focus areas to change with time as 

illustrated in Figure 4. 

As the programme progresses, more time will be spent on Early Detection and contingency 

planning as the programme is now working through the ‗backlog‘ of species that have not been 

fully assessed. The existing high level of identification of species will tail off as species currently 

not identified are checked and verified. Subsequent to this high work load the need for 

identification of species will increase alongside the number of new species being detected. 

Although it is still to be formally assessed, we believe EDRR has the potential to continue to 

be an important feature of the control of invasive organisms in South Africa for many years to 

come. 

Figure 4 - Anticipated change in work load on each component as the EDRR programme 

develops 

References 

de Janasz SC & Sullivan SE (2004) Multiple mentoring in academe: Developing the professorial network .Journal 

of Vocational Behavior 64, 263–283 

Department of Water Affairs Website http://www.dwaf.gov.za/wfw/ (Accessed July 2010) 

Geber HM (2004) Mentoring of early career academics in South African Higher Education: A Transformation 

Strategy. Ph.D. Thesis, University of the Witwatersrand, Johannesburg. 

Geber HM (2003) Fostering career development for Black academics in the New South Africa. In: Global 

perspectives on mentoring: Transforming contexts, communities, and culture, eds. F. Kochan and J. 

Pascarelli. Information Age Publishing. 

Henderson L (2010) Surveys of alien weeds and invasive plants in South Africa, - Southern African Plant Invaders 

Atlas (SAPIA) Phase II, Final Report to Working for Water April 2005 – March 2010 

Jacobs, Van Wyk and Wilson in these proceedings Should Melaleuca be an eradication target in South African 

fynbos? Looking beyond population data. 

Le Roux JJ, Geerts S, Ivey P, Krauss S, Richardson DM, Suda J, & Wilson JRU (2010) Molecular systematics and 

ecology of invasive Kangaroo Paws in South Africa: management implications for a horticulturally important 

genus. Biological Invasions, DOI 10.1007/s10530-010-9818-4 



188

National Environmental Management: Biodiversity Act, Act 10, 2004, Government Gazette, Vol. 467 Cape Town 7 

June 2004 No. 26436 http://www.environment.gov.za//PolLeg/Legislation/2004Jun7_2/Biodiversity %20Act 

-7%20June%202004.pdf 

Nel JL, Richardson DM, Rouget M, Mgidi TN, Mdzeke N, Le Maitre DC, van Wilgen BW, Schonegevel L, 

Henderson L & Neser S (2004) A proposed classification of invasive alien plant species in South Africa: 

towards prioritizing species and areas for management action. South African Journal of Science 100 

January/February 2004 

Stone K, & Coetzee, M. (2005) Levelling the playing field: reducing barriers to mentoring for women protégés in 

the South African organisational context. SA Journal of Human Resource Management 3(3), 33-39 

Wilson et al. these proceedings Eradication and monitoring of Australian Acacias in South Africa as part of an 

EDRR program, can species with long-lived seed banks be eradicated? 

Wittenberg R, & Cock MJW (eds.) (2001) Invasive Alien Species: A toolkit of Best Prevention and Management 

Practices. CAB International, Wallingford, Oxon, UK, xvli – 228. 

Zenni et al. (2009) Evaluating the invasiveness of Acacia paradoxa in South Africa. South African Journal of 

Botany 75, 485–496. 



189

Appendix - EDRR is actively working on about 18 invasive alien plant species as of July 2010, either in terms of assessing current 

status and future risk (step 3 on Fig. 2); or containment or eradication plans are being implemented (step 4). Plans are in place to start 

full scale assessments on several other species not listed here in the next year, while in some cases taxonomic issues relating to the list 

below still need to be resolved (step 2). 

Species Biome Categorisation 

under South 

African law 1 

Range size 

(quarter degree 

grid cells) at 

project 

initiation 2 



Records of naturalisation or 

invasiveness 4 

Acacia implexa Fynbos 1a 2 South Africa only (Wilson et al. these 

proceedings) 

Acacia paradoxa Fynbos 1a 2 Australia (extra-limital), U.S.A. 

Acacia stricta Fynbos 1a 5 

(California), Israel, New Zealand, South 

Africa (Zenni, et al. 2009; Wilson et al. 

these proceedings) 

New Zealand, South Africa (Wilson et al. 


Anigozanthos flavidus / Fynbos Surveillance list 1 Australia (extra-limital), South Africa (Le 

Anigozanthos rufus 

Roux, et al. in press) 

Banksia ericifolia Fynbos Not listed 1 South Africa only 

Campuloclinium 

Grasslands 1a or 1b depending 85 Southern Africa only 

macrocephalum 

on the province 

Cylindropuntia fulgida var. Arid 1b 7 (variety not Australia, South Africa 

mamillata 

specified) 

Cylindropuntia rosea / Arid Genus on 0 Australia, Cuba(?), South Africa 

Cylindropuntia tunicata 

surveillance list 

Fucraea gigantea (Fucraea Tropical Not listed 0 Various 

foetida) 

coastal 

Hydrilla verticillata Water bodies 1a 2 South Africa, Mozambique 

Lythrum salicaria Wetlands 1a 1 Various 

190

Melaleuca ericeafolia Fynbos 

wetlands 

Surveillance list 0 Present in 5 countries (GBIF), Australia 

(extra-limital), but not currently classified 

as invasive in this country (Jacobs et al. 

Melaleuca quinquinerva Fynbos Surveillance list 0 


Present in 22 countries (GBIF) (Jacobs et 

wetlands 

al. these proceedings) 

Spartinia alternifolia Estuaries Not listed 0 Various 

Tephrocactus articulatus Arid 1a 5 South Africa 

Triplaris americana Tropical 

coastal 

1b 1 Australia, Hawaii? 

1 

According to the National Environmental Management: Biodiversity Act, Draft Alien and Invasive Regulations 2009. 1a species 

require compulsory control; 1b species are controlled as part of an invasive alien species control programme; the surveillance list 

refers to species that have been identified as potential risks. 

2 

EDRR was initiated in April 2008. Data are from the South African Plant Invaders Atlas (SAPIA), http://www.agis.agric.za/wip/. 

ARC-Plant Protection Research Institute, Pretoria. 

3 

New records can be from any source, and need not be attributable to EDRR, but the values here are as recorded by EDRR staff (in 

some cases prior to integration with SAPIA). 

4 

Data are from Global Compendium of Weeds, http://www.hear.org/gcw, accessed 20 July 2010; and the Global Biodiversity 

Information Facility, http://data.gbif.org, accessed 20 July 2010. 



191

The NOBANIS gateway on invasive alien species and the development of a European Early 

Warning and Rapid Response System 

Melanie Josefsson 

Swedish Environmental Protection Agency, Department of Natural Resources, SE106 48 

Stockholm, Sweden. E-mail: melanie.josefsson@snv.slu.se 

NOBANIS (the European Network on Invasive Alien Species) is a gateway to information on 

invasive alien species in Europe. Eighteen countries in North and Central Europe participate in 

the NOBANIS network, which originally was funded by the Nordic Council of Ministers (2003- 

2008), but is now funded by member countries. 

The focus of NOBANIS is to provide information on IAS for environmental managers working 

with preventative measures, control and eradication of IAS in all environments. The NOBANIS 

gateway provides information on alien species and populations in distributed but integrated 

databases with more than 14,520 records, fact sheets on 59 of the most invasive alien species in 

the region, an identification key for alien species in the marine environment and a library on 

national regulations and literature. A charting function enables the user to produce figures from 

the databases for example trends in introduction, pathways of introduction, habitats invaded. 

After a workshop on developing a European Early Warning and Rapid Response System in June 

2010, the focus of work within NOBANIS is continued improvement of the databases and on 

developing the early warning aspects of the gateway. A quarterly newsletter is produced to 

facilitate exchange of information. A ―species alert‖ function on the portal is under development. 

A pilot project has been initiated to implement a biogeographic approach in the databases to 

facilitate early warning functions in the future. 



192

From mediocrity to notoriety – the case of invasive weedy rice (Oryza sativa) biotypes in 

Malaysian rice granaries 

Baki B. Bakar 

Institute of Biological Sciences, University of Malaya 50603 Kuala Lumpur, Malaysia, E-mail: 

baki@um.edu.my 

Introduction 

Weedy rice (WR), Oryza sativa L., aggregates are a scourge in the Malaysian 

rice granaries. We collated and analyzed field survey and experimental data on 

the extent of the infestation, the economic losses and the economics of control 

of WR for the past 20 years. Albeit season-mediated fluxes with erratic 

infestations from small pockets measuring less than 50 ha in total in 1987 to ca. 

56,790 ha out of 230,000 of rice granaries in 2009 in Malaysia. Different 

degrees of both season- and field-mediated infestations were displayed, ranging 

from 50%. Based on conservative estimates of 5% yield loss due to 

WR infestation nationwide and the national average of 5 tons/ha, a yield loss of 

0.25 tons/ha or 115,000 tons/year of rice yields valued at MYR172.5 

million/year based on the government guaranteed price of MYR1,500/ton can 

be envisaged. The average input and labor costs of thorough land preparation, 

herbicides and application as well as manual weeding, roughing and panicle 

slashing of WR amount to MYR1,250/ha or MYR285.7 million/year 

nationwide. These costs augmented with monumental yield loss impacted not 

only on farmers‘ income but also the national target of self-sufficiency level of 

86% of rice production by 2010. Future trends are discussed. 

“If there is no man, there will be no woman. 

If there is no weed science there will be no agriculture. 

If there is no agriculture, there will be no mankind” (Baki B.B. 2005). 

Oryza sativa or weedy rice (WR) aggregates including red rice (RR) and their wild relatives 

remain a universal scourge in rice fields worldwide. They grow side-by-side as sympatrics 

where the crop is direct-seeded (Vaughan & Morishima 2003; Baki & Shakirin 2010). Together 

they represent some of the noxious and millennial weed species (Gressel 2000) in rice 

ecosystems globally (Chin et al. 2000; Baki 2005; Shakirin 2009; Baki & Shakirin 2010). The 

spread of weedy rice in Malaysia became significant due to the shift of rice culture from 

transplanting to direct seeding (Azmi et al. 2000). The cultural practices of direct- and volunteer 

seeding in the 1980‘s is suspected to be the most plausible uses for the origin and spread of 

weedy rice in Malaysia. In Malaysia and in the nieghboring countries such as Thailand, Vietnam, 

Philippines, and elsewhere, the practices of dry-seeding culture using seeds from previous season 

are thought to be the most important factors causing the infestation of weedy rice in rice crop 

(Sadohara et al. 2000). The use of contaminated rice seeds and the movement of farm machinery 

between granaries are also factors related to this problem. With shorter maturation period 

compared with commercial rices and the manifestation of easy grain shattering, weedy rice 



193

seems to be able to out-compete commercial rices. Since its first reported occurrence in 1987 by 

Wahab & Suhaimi (1991) in Malaysia, weedy rice inflicts yield losses to the rice crop, thus 

representing one of the most serious threats to rice production in Malaysia. Weedy rice 

infestations impact on rice production. Impact studies of WR or RR on the rice industry 

registered measurable loss in terms of yields and quality of harvest by farmers (Fisher & 

Ramirez 1993; Chin et al. 2000; Baki 2004; Shakirin 2009). Weedy rice infestation reduced 

growth and yields of commercial rice and is undesirable to rice farmers, to the milling industry, 

and to consumers alike. These reductions are augmented with parallel increase in the costs of 

crop management and care. Azmi et al. (2000) recorded cultivar-mediated variations in yield 

reductions due to WR interference, ranging from 8 to 34%. Weedy rice contaminants in the rice 

harvest lead to quality reduction and lower market value. Baki (2004, 2007) estimated that 5% 

field infestation of weedy rice in Malaysian rice fields led to an economic impact in yield loss of 

ca. 64,880 tons of rice valued at MYR 137,876,375/year or US$35,999,053/year. 

Millers complain that WR reduce total and head rice recovery, and lowers grain quality 

(Menzes et al., 1997; Azmi, pers. comms.), besides inflating the processing cost when WR are 

separated from milled rice. The Malaysian rice millers imposed premium penalties in grain 

harvest contaminated with weedy rice, thereby fetching lower prices at the mills (Azmi, M. pers. 

comm). 

This communication traces the infestation of weedy rice from a non-entity among weed 

populations in the late 1980s to its current status as the most important invasive weed in the 

Malaysian rice granaries. A brief treatment on weedy rice biotypes or aggregates, and socioeconomic 

impacts and losses due to ensuing infestation of weedy rice in the Malaysian rice 

ecosystems are also made. Management protocols of weedy rice in the rice eco-systems for the 

past decades with special emphasis on direct, and indirect, preventive, and substitutive agrotechnical 

and cultural methods of control of weedy rice were made. The rationale and approaches 

of integrated weed management including the economics of control of weedy rice are also 

discussed. The paper ends with a note on future challenges faced by the rice industry in 

managing weedy rice in Malaysia. 

Weedy rice aggregates, impacts and status of infestation in Malaysia 

“We sow rice seeds but weeds grow and establish” (Malay proverb). 

Weedy Rice Aggregates -Infestation and Spread. While pockets of Oryza officinalis, O. 

rufipogon, O. nivara grow sympatrically with commercial rices, weedy accessions of O. sativa 

infest extensively the Malaysian rice fields (Watanabe et al., 2000; Baki, 2006b, Shakirin 2009). 

Since its first detected occurrence in Tanjung Karang rice field, weedy rice has spread to other 

rice granaries in Peninsular Malaysia. The infestation has spread to Muda Agricultural 

Development Authority (MADA) MADA in 1990, Besut in 1995, Sungai Manik/Kerian in 1996, 

Seberang Prai in 1997, Seberang Perak and Kemubu in 2001 (Baki, 2006b) (Table 1). Albeit 

season-mediated fluxes with erratic infestations of the scourge from small pockets measuring 

less than 50ha in total in Selangor North-West Project in 1987 to ca. 49,000 ha out of 230,000 ha 

of rice granaries in Malaysia in 1997. The parallel figures of infestation for 2007, 2008 and 2009 

were ca. 11,735 ha, 32,370 ha and 56,790 ha, respectively. Different degrees of both season- and 



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field-mediated infestations were displayed, ranging from 50%. Intriguingly, the scourge 

has spread to the rice fields in northern Sabah some 3,000 km away (Baki, unpublished data 

2010). In the Muda region of Kedah, weedy rice was present in 82% of the farm blocks in 2001. 

About 91% of the farm blocks were infested by weedy rice in 2005 with 88% of the farm blocks 

having at least a 10% infestation (Baki et al., 2000; Shakirin, 2009; and Baki & Shakirin (2010). 

In Selangor North West Project, the infestation acreages dropped in 2000 and this was 

principally attributed to a successful weed control by farmers and consistent campaigns and 

advice by the government and other related organizations to alleviate the problem in the area 

(Azmi et al., 2004). The chronological appearance of weedy rice in Peninsular Malaysia was 

described by Baki (2006b)(Fig. 1). 

1999 

1996 

1997 

198 

8 

1996 

Figure 1 - The chronological occurrences of weedy rices in the granaries of Peninsular 

Malaysia (after Baki 2006b). PA1, PA2…PA125, weedy rice accessions; [●], rice-growing 

areas and granaries. 

200 

1 



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Weedy Rice Aggregates - Origin and Morphological Traits. The origin of weedy rices in 

Malaysia is essentially unknown and this intricacy remains to be unfolded. Weedy rices comprise 

2 principal categories, one sympatric with wild rices, and another which occur in localities where 

no wild rice is found. In the former case genes introgression occurs commonly from the 

commercial varieties domesticated to the wild type, but the opposite direction of gene flow is 

rare because of the low fertility of the pollen grains and the high out-crossing rate in the 

perennial type type. The recurrent gene flow in this direction may lead to the production of a 

weedy type having an indica-type nuclear genome and a japonica-type cytoplamic genome 

(Sato, 2000). Abdullah et al. (1996) and Vongsaroj (2000) argued that the origin of weedy rice 

was through the segregation of the deciduous ―off-types‖ from extensively planted cultivars 

during the periods of volunteer seeding. 

Table 1 - The chronological estimates of weedy rice infestations in Peninsular Malaysia from 

1995 to 2007 (updated from Shakirin 2009; Baki & Shakirin 2010) 

Granary Area 

Degree of infestation (ha) 

(ha) 1995 1996 1997 1998 1999 2000 2001 2002 2003 2005 2007 

MADA** 96459 ? 300 225

seedling stage. The gross morphological differences of WR biotypes compared with the 

commercial varieties at the tillering and post-tillering stages are the following: longer and 

slender tillers, leaves are more often hispid on both surfaces, taller plant stature, the easyshattering 

or deciduousness traits of seeds, pigmentation of several plant parts, principally the 

pericarp, and the presence of awns of variable lengths. These traits in many instances, make 

weedy rices more recognizable compared with the commercial varieties. Some of the undesirable 

traits and evolutionary characteristics of WR in are illustrated in Table 2. 

Table 2 - Undesirable traits and evolutionary characteristics of weedy rice (modified from 

Watanabe, 1995) 

Type of Characteristics Traits Characteristics Type of Interference 

Morphological Culm Tall, prone to lodging Competitive edge over rice 

Grain Variable length Reduce grain quality 

Pericarp Pigmented, coloured Lower market price of grains 

Awn Presence/absence 

Plant mimicry Mimics rice crop Difficult to identify 

Ecological Threshability Grain deciduousness Reduce rice yield, increase 

seedbank 

Dormancy Seed dormancy Difficult to control 

Seed longevity Viable in soil for 

months 

Difficult to reduce size of 

seedbank 

Physiological Germination Variable Adapted to wet-seeded fields 

Herbicide Tolerant Less effective to herbicides, 

normally used in rice 

cultivation 

In the late 1980s and 1990s in Peninsular Malaysia weedy rices used to be taller than 

cultivated rice and was therefore easily identified. Earlier work by Mislamah & Baki (1999) 

recorded no less than 27 taller biotypes of weedy rices in Peninsular Malaysia. The new biotype 

accessions stand were observed to be as tall as the cultivated rice which became a new threat for 

the rice production in Malaysia (Baki & Shakirin, 2010). Generally, these new biotypes of weedy 

rice display strong crop mimicry with the existing cultivated rice, namely, MR220, MR219, and 

MR84 with similar heights increasing the difficult in identifying them even at maturity. Baki & 

Shakirin (2010) identified no less than 16 such biotypes. These biotypes display open and close 

panicle type. The grains are short or long with or without awns, and the pericarp colors are red or 

white. All biotypes showed >50% grain shattering except the weedy rice Acc. 15. 

Integrated Management of Weedy Rice 

“The story of agriculture is indeed the story of weed interference “(Dekker 1997). 

No single weed management component or control method can effectively control WR in rice 

(Azmi et al., 2000; Noldin, 2000a, 2000b; Valverde, 2004). Farmers normally employ a battery 



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of indirect and direct control methods to achieve satisfactory results. These include, principally, 

the agro-technical and preventive methods comprising land preparation and tillage, water 

management and manual weeding; crop manipulation through seeding rates, planting density, 

and a choice of competitive cultivars; and chemical weed control (Noldin, 2000 a,b). 

Indirect Methods of Control: Preventive, Substitutive, Agro-technical and Cultural. The 

indirect control measures of WR are shown in Table 3. Each of these methods has its own merits 

and demerits, and when used within the context of integrated weed management systems, should 

augment each other in reducing WR populations. 

Preventing the introduction of invasive weedy rice is the most effective method for their 

management and is an essential component of a noxious weed management strategy. However, 

this is difficult to enforce. The major elements of a prevention programme are to stop the 

introduction of weedy rice seeds or vegetative propagules, to reduce the susceptibility of the 

ecosystem to invasive weedy rice establishment, and to develop effective education and 

extension materials and activities, and establish a programme for early detection and monitoring. 

Strict quarantine enforcement preventing free movement of animals, vehicles and farm machines 

from infested lands should also be carried out. This is a difficult and an expensive routine to 

carry out. This would mean only certified high quality weed-free rice seeds should be planted by 

farmers (Baki et al., 2000; Vongsaroj, 2000). This is an achievable target with close monitoring 

and political will of the policy makers especially the quarantine office and the extension agents. 

In Malaysia only 35 -40% of the certified seeds are available to rice farmers and such situation 

aggravates further weedy rice problems now and for the future. The fact that certified rice seeds 

are not easily available or inadequate in supply and the fact that farmers rely on their own 

collection of seeds for planting, higher risks of weedy rice being a contaminant. 

Seed longevity in the soil is an additional character that enables population persistence over 

cropping seasons. Furthermore, the inherent seed dormancy in some variants of weedy rice 

makes control measures more difficult in rice cultivation. Reducing seed longevity or seed bank 

is a long-term strategy to reduce the deleterious effects of weedy rices on their commercial 

counterparts. This is a pre-requisite to long-term eradication of the scourge in the rice fields. 

Therefore, holistic control measures have to be developed which integrate indirect control such 

as thorough land preparation, high quality seeds, appropriate seeding rate and crop establishment 

technique. 

Cultural practice of WR include the use of stale bed techniques, water-seeded rice with pregerminated 

seeds, crop rotation, and management practices to reduce WR seed bank. WR seed 

longevity increases when the seed is buried deep in the soil (Nordin, 1995, Watanabe et al., 

1996; Azmi et al., 2000; Vongsaroj, 2000). Following harvest, rice fields infested with WR 

should be left as a fallow, leaving the WR seeds near or on the soil surface, allowing them to 

germinate thus losing their viability faster than when buried deep in the soil. 

The size of seed bank plays an important role in determining the severity of infestation by 

weeds, including WR. Proper tillage must be undertaken to reduce this seed reservoir. Land 

preparation, especially puddled soils and harrowing, provides a weed-free environment for 

planting and often aids in the good crop establishment while minimizing weed growth and 

proliferation in the established crop. Azmi et al. (2000) advocated sequential tillage operations 



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within the framework of integrated weed management to reduce WR populations in directseeded 

fields (Fig. 2). The initial tillage should be shallow enough to encourage sizeable 

germination of WR seeds while subsequent tillage must be thorough enough to ensure that all 

volunteer seedlings are annihilated. Three rounds of tillage at 10-day intervals are effective in 

reducing WR populations. To ensure total kill, pre-planting or pre-seeding sprays with nonselective 

herbicides such as glyphosate or glufosinate ammonium are occasionally needed. 

Minimum or zero tillage (MZT) systems are used in many areas with severe WR problems. This 

is done either by seed drilling or water-seeding 15 - 20 days after land preparation and spraying 

of the fields with non-selective herbicides such as glyphosate or glufosinate ammonium (Nordin, 

2000; Azmi et al., 2004). Appropriate water management is singularly important for controlling 

weeds irrespective of rice cultures. Inundation of rice fields suppresses weed emergence and 

establishment, including WR. Rice fields should be flooded soon after rice emergence, 

preferably at 5 -10 cm until booting stage, otherwise WR control is ineffective. In water-seeded 

rice, pre-germinated seeds are broadcasted in the water in leveled fields soon after seedbed 

preparation. This system warrants permanent levees, and offers one of the best alternatives for 

WR control in Brazil and elsewhere. Field drainage is monitored so as not to expose soil to air 

and increases in oxygen concentration in the soil, thereby stimulating WR germination. 

Table 3 - Components of indirect control methods of weedy rice (modified from Baki, 2006b). 

Control components Merits / Demits 

Prevention/Eradication Quarantine measures, difficult & expensive to enforce; use of 

WR- free certified seeds effective in long-term control, require 

effective quarantine and extension services. Panicle cutting of 

WR before maturity; expensive to carry out in large farms. 

Tillage/Stale seedbed 

Water management 

2-3 rounds of tillage, augmented by blanket or spot sprays 

with low doses of glyphosate. Field levelling is necessary. 

Tillage implements should be free from WR contaminants, 

difficult to enforce in systems where farmers hire 

tillage/harvesting machines. 

Fields inundated 5 -10 cm, 5 days after wet-seeding or 14 days 

after dry seeding. Inundation of rice fields suppresses WR 

emergence and establishment. 

Seeding technique/rate seeding Pre-germinated wet seeding gives better seedling establishment 

than dry of 80-100kg/ha vis-à-vis the optimum 60kg/ha seeding 

rate as insurance against establishment uncertainties. 

Crop rotation Rice-maize rotation grown at alternate years for 4 years 

controlled WR effectively and this brings about changes to the 

overall crop-weed ecology. Allows rotation of herbicides; 

prevent subsequent build-up of weed resistance. Farmers plant 

high-priced market-driven produce, rather than rice for better 

income. 

Choice of cultivars/planting date Competitive short maturation cultivars can out-compete WR, e.g. 

MQ 95. 



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Our limited studies indicated that two rounds of thorough soil ploughing or rotovation in the 

land preparation followed by leveling would enable weedy rice seeds to germinate and establish 

before herbicidal treatments with non-selective herbicides such as glyphosate (0.8 – 1.7 kg ae ha - 

1 ) or glufosinate ammonium (0.6-1.1 kg a.i. ha -1 ) 10-14 days later gave measurable control 

against WR seedlings at 3-4 leaf stage. 

An important component in the indirect cultural and preventive weed control methods in rice is 

the use of suppressive and competitive rice cultivars against WR. A short-maturing variety, such 

as MQR 95, out-competes WR, and this will indirectly help reduce the WR seed bank where 

early harvesting of the rice crop when WR is still at its flowering stage (Azmi et al., 2000). 

Puckridge et al. (1988) recommended the planting of cultivars with distinguishing colour traits 

(e.g. Khao Niew Dam), such as a cultivar with purplish stems and leaves to differentiate crop 

from weedy forms, to aid in manual weeding. However, this tactic will only be successful in the 

long term and if hybridization with wild rice is prevented, with prudent choice of planting dates. 

Figure 2 - Integrated approach in weedy rice control in direct-seeded fields in Malaysia 

(after Azmi et al., 2000). 

Developing Herbicide-Tolerant Rice Cultivars. Malaysia through the Malaysian 

Agricultural Research and Development Institute (MARDI) has developed some promising lines 

of imidazolinone- resistant rice biotypes. This was made possible by crossing Clearfield® rice 

cultivar with locally produced modern rice cultivars (Azmi, M., pers. comm. 2010). So far five 

such lines have been identified showing resistance to imidazolinone. According to Croughan 

(1994), an ethyl methane sulfonate-induced mutation of the acetolactate synthase (ALS) gene is 

the basis for herbicide resistance in the imidazolinone rice varieties, conferring resistance to 

imidazolinones and certain sulfonylurea herbicides. These Malaysian IMI-rice cultivars are yet to 

be released to the rice farming communities. Due to the fear of possible introgressions with 



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weedy rice, the arguments made by Riches & Valverde (2002) and Madsen et al. (2002), among 

others, that prior to the introduction of HR crops including HR/HT rice, their short- and longterm 

risks should be thoroughly assessed should be followed. I believe that scientists at MARDI 

have yet to undertake such risk analyses following the release of IMI-rice to the rice farmers in 

the country. Generally, the cultivation of HR/HT rice would lead to parallel increase of volunteer 

rice crop problems (Sankula et al., 1998). Further, WR plants may emerge out in frequent timemediated 

flushes, and hybridization, however, low in frequency, may still prevail. If we were to 

follow the arguments of Madsen et al. (2002), using a ten-year run, predicting that resistance to 

glufosinate would occur within 3 -8 years of monoculture, then the basis of releasing IMI-rice in 

Malaysia would equally be flawed and risky with the possibility of weedy rice biotypes acquiring 

resistance over time. There are enough evidences that the introduction of these herbicide-tolerant 

(HT) or herbicide-resistant (HR) rices accentuate the risks of gene flow into weedy relative, the 

WR (Gealy et al., 2003; Shivrain et al., 2004) or the potential development of herbicide-resistant 

or ferality in WR (Gealy & Estorninos, 2004). Such risks are monitored through simple sequence 

repeat (SSR) marker and phenotypic analyses of segregating populations to identify, quantify, 

and track the WR hybrids in farmers‘ and research fields. Being sympatrics, rice and WR are 

primarily self-pollinated, but can cross-pollinate one another, providing avenue for the transfer of 

genetic traits such as herbicide resistance from rice to weedy rice. 

Direct Methods of Control. Physiological similarities between WR and cultivated rice limit 

chemical control options (Jordan & Sander, 1999). With the absence of herbicides for WR 

control in commercial rice, Malaysian rice farmers are encourages to rotate rice fields with other 

crops. This option is not readily acceptable to Malaysian for the very reasons of irrigation 

regimes in the rice granaries although such rotation of crops not only will bring about changes to 

the overall crop-weed ecology, but also prevent the continuous use of same herbicide(s) and the 

subsequent build-up of weed resistance (De Datta & Baltazar, 1994; Valverde et al., 2000). 

Except for glyphosate and glufosinate ammonium, most of graminicides for WR control are 

used in the presence of the rice crop. Application of oxadiazon at 250 g a.i. ha -1 or oxadiargyl at 

72 -100 g a.i. ha -1 to control WR, obtained significantly higher rice yields than the control (Chin 

et al., 2000; Azmi et al., 2000). Slight injuries to cultivated rice were observed under drained 

field conditions. Measurable control of WR in Malaysia was reported with molinate at 4.5 kg a.i. 

ha -1 and thiobencarb at 300 g a.i. ha -1 , respectively (Azmi et al. 2000). Graminicides such as 

clethodim, fluazifop-P, quizalofop-P and sethoxydim were more efficient for the control and 

seed head suppression of WR especially at booting stages than when applied at early growth 

although the efficacy was dependent on application timing and environmental conditions during 

treatment. High levels of WR control were ranging from 84 to 92% with PRE applications of 

alachlor, dimethenamid, metolachlor, acetolachlor at the respective rates of 2.4, 1.4, 2.5, and 1.5 

kg a.i. ha -1 . The parallel figures of WR control with POST applications of glyphosate, 

glufosinate, or quazilafop-ethyl were 92, 89, 81 and 100%, respectively. Pre-flood applications 

of glufosinate at 0.42 kg ha -1 at 2-3 leaf rice initially, and at the early tillering stage, and 

glyphosate at 0.42 - 0.84 kg ha -1 also gave consistent control of WR. 

Manual roughing of WR seedlings or plants before heading are being practiced by farmers in 

tropical Asia and Latin American countries (Azmi et al., 2000a; 2000b). This method of control 

is limited as it is labor intensive, and can be expensive, especially in countries relying on foreign 



201

labor. I believe strongly that if back-breaking manual weeding is still instituted in weed control 

against WR or any weed species for that matter in this so called post-modern era of the new 

millennium, then something is wrong with our attitude towards humanity as a whole. Either the 

world community is not sensitive to the needs and suffering of the human race, or there are real 

gaps in our extension activities to help modernize farmers weed management effort and boost 

their rice yields. 

Economics of control of Weedy Rice and impact of its infestation in Malaysia 

The costs incurred to manage weedy rice vary according to the granaries. These differences 

stem out partially on the level of infestation prevailing in the rice fields, and also in the costs of 

the labor input to carry out chemical, manual weeding or roughing and panicle slashing of weedy 

rice. Labor is increasingly scarce in Malaysian rice fields due partly to the aging of farmers. 

Lately foreign labor from neighboring countries is contracted in rice farming from land 

preparation to harvesting, even with combine harvesters. Recent surveys (1990, 1995, 2000, 

2005, and 2010) conducted in Malaysian rice granaries indicated that the costs of herbicide 

sprays ranged from MYR 15 – MYR 50/ha depending on the localities Manual roughing and 

panicle slashing of weedy rice cost MYR 500-MYR 650/ha. If the costs of thorough land 

preparation as indirect costs of weedy rice management as well as herbicide inputs are taken into 

account, the total costs would be in the region MYR 1000 –MYR 1250/ha. On the higher 

extreme, the costs of managing weedy rice in the country would be estimated at MYR285.7 

million nationwide based on rice growing areas of 624,000 ha. 

With granary- and season-mediated differences in infestation levels of WR, it is quite difficult 

to ascertain the yield loss due to WR in Malaysian rice fields. Our conservative estimate of 5% 

field infestation of WR nationwide would inflict yield loss of no less than 0.25 tons/ha based on 

the national average yield of 5 tons/ha or 115,000 tons/year of rice yields valued at MYR172.5 

million/year based on the government guaranteed price of MYR1,500/ton. Our surveys in 2000, 

2003, 2005, and 2007 registered field WR infestations ranging from 25 to 35 % with the 

respective acreages of 3265, 8144, 8902, 9832, and 14,280 ha (Table 1). However, there were 

many rice fields in the country that registered infestation ranging from 50% infestation, depending on the levels of control undertaken by the farmers 

either through agro-technical or herbicide-based control measures. Our field studies indicated 

that with 35% of WR infestation, density-mediated yield losses would in the regions of 50-60%, 

or 3.20 - 3.84 tons/ha/season valued at MYR4,800 – MYR5,670/ha/season. Baki (2007) 

estimated that 5% field infestation of weedy rice in Malaysian rice fields led to an economic 

impact in yield loss of ca. 64,880 tons of rice valued at MYR 137,876,375/year or 

US$35,999,053/year. 

Additionally, weedy rice infestations incur further costs to Malaysian rice farmers. Farmers 

need to practice thorough land preparation, water management, and herbicide-based weed 

management to ensure total control of weedy rices and other weeds prior to seeding. Measures of 

proper agronomic practices and proper crop care will inevitably lead to more hours spent in the 

fields. For some farmers these valuable hours should be spent elsewhere to generate better 

income or better-paid jobs. In the same vein, inculcation of the zero-tolerance concept and 

practice of weed infestation among farmers is difficult and expensive, especially among aging 



202

ice farmers in the country. This failure will aggravate weedy rice problems for many years to 

come. 

One of the actions needed to bring down the infestation of WR is to change the rice culture 

presently from direct seeding to transplanting. Such a change would enable manual weeding to 

be done under transplanting rice culture compared with direct seeding. Transplanting rice culture 

would incur extra cost to rice farmers ranging from MYR850/ha to MYR1,200/ha compared with 

MYR200/ha in direct seeding rice culture, inclusive of the costs of seeds. 

Future Challenges 

The new millennium witness food security and food scarcity (FSFS) as major issues haunting 

the world populace at large and Malaysia is no exception. With our current needs exceeding our 

domestic supply, Malaysia imports about 27% of the rice from Thailand and Vietnam, and lately 

from Cambodia and Myanmar. The government targets 86% of self-sufficiency level (SSL) in 

rice by2010. This aim should be attained through serious action and mitigation to increase rice 

supply with more than US$1 billion allocation to improve infrastructures, drainage and 

agricultural inputs. It becomes the responsibility of rice farmers and those involved in the rice 

industry to produce enough rice for domestic consumption. The demand for rice outclassing 

supply coupled with the increasing world‘s population spell uncertainty in the world rice market. 

Malaysia being a net rice importer is likely to be affected by this spin-off. Recently, two of the 

world‘s biggest supplier of rice, Thailand and Vietnam, plagued by drought and floods, 

announced shortfalls in supply, hence the reduction in export quantity of the commodity. 

A perennial issue facing rice farmers in Malaysia is pest outbreak with weeds being the most 

important. The advent of recalcitrant, hard-to-control millennial weeds like WR, coupled with 

increasing incidences of herbicide-resistant weed species in rice ecosystems worldwide including 

Malaysia are challenges that the rice industry at large has to face, requiring farmers to invest 

higher input costs to control these weeds. The ability to implement control measures against WR 

with minimal input costs yet inflicting no yield loss to commercial rice warrants the commitment 

of farmers, extension agents and other players in the rice industry. The WR infestations inflict 

yield loss to a variable degree. The ability of extension agents to inculcate awareness among rice 

farmers that WR infestations inflict yield loss to a variable degree, and that integrated control 

measures against the scourge must be carried out early enough, are key challenges facing the rice 

industry. This is especially important to small-scale peasantry rice farming communities, where 

state of the art control inputs and credit facilities are not always at their disposal. Farmers must 

be advised that intensive rice monoculture breeds resistance in other weed species. The use of 

certified WR-free rice seeds, the sharing or use of WR-clean tillage and harvesting implements, 

and cutting of immature WR panicles are other ways to prevent the spread in non-infested fields. 

Truly the advent of invasive WR from a non-entity in the late 1980s to a largely recalcitrant 

scourge in the new millennium is worrisome to the players in the rice industry. This is 

aggravated by increasing costs of inputs in rice production in the country. There is a need to 

institute aerobic rice production in the country in the face of increasing competition for water – a 

move that is likely to increase WR and other millennial weed problems further. Intensive 

research to find solutions to WR problems based on IWM concepts and practice will go a long 

way to help achieve the 100% SSL in rice production in the country. 



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With innumerable accessions the deciduous ―off-types‖ of WR segregants from extensively 

planted cultivars during the periods of volunteer seeding (Abdullah et al., 1996; Vaughan et al., 

2001; Valverde, 2004; Shakirin, 2009), the problems of WR in rice fields are here to stay. Our 

ability to manage these WR populations below the economic threshold levels season after season 

requires the sharing of knowledge and experience for the common good of humanity. The 

establishment of global databases and of a WR management network is one way that the entire 

world rice community can share and benefit from each other. The MED-Rice is one of such 

network. Such networking facilities are not common in rice-growing areas of the developing 

countries for a variety of reasons. The technological gap between the rice-growing areas of USA, 

Europe and Japan, and those in the developing world like Malaysia is one reason for the 

―apparent lack of dialogue and cooperation‖ to solve WR problems worldwide. The weed 

science fraternities, especially those working in WR management need to bridge this gap. 

I can say with pride that rice farmers in Malaysia enjoy not only price-support system and 

subsidies in many forms from the government but also good extension and technical-support 

services from government-run agencies. In this way fair price to the farmers are assured while 

providing affordable rice to the Malaysian consumers. 

References 

Abdullah MZ, Vaughan DA, Watanabe H & Okuno, K (1996) The origin of weedy rice in Peninsular Malaysia. 

MARDI Res. J. 24(2), 169-174. 

Azmi M, Abdullah MZ & Fujii Y (2000) Exploratory study on allelopathic effect of selected Malaysian rice 

varieties and rice field weed species. J. Trop. Agric. & Food Sci. 28, 39-54. 

Azmi M, Mislamah AB & Mohd Rafee U (2004) A Technology Manual For Weedy Rice Management. MARDI- 

Department of Agriculture, Publication, Kuala Lumpur, 36p. 

Baki BB (2005) The world‘s landscapes of weedy rice: An overview. Proc. 20 th Asian-Pacific Weed Science Society 

Conference (Ho Chi Minh City) 1, 45-52. 

Baki BB (2006a) Shaping the Future of Weed Science to Serve Humanity. University of Malaya Press, Kuala 

Lumpur, 178p. 

Baki BB (2006b) Weed Ecology and Management in Rice Ecosystems. University of Malaya Press, Kuala Lumpur, 

373p. 

Baki BB (2007) A Review on Invasive Plants in Malaysia. Abstract – International Symposium on Invasive Alien 

Plants in Asia, 5-7 October 2007, National Institute of Agricultural and Environmental Sciences (NIAES), 

Tsukuba, Japan. 

Baki BB, Mislamah MA & Azmi M (2000) Weedy rice (Oryza sativa L.) in Peninsular Malaysia. In: Wild and 

Weedy Rice in Rice Ecosystems in Asia – A Review (Baki, B.B., Chin, D.V. & Mortimer, M., eds.). IRRI, 

Manila, Philippines, pp. 51-54. 

Baki BB & Shakirin MM (2010) Spatio-temporal Distribution Pattern of New Biotypes of Weedy Rice (Oryza 

sativa L.) in Selangor North-West Project, Malaysia. Korean J. Weed Science (2010)(in press). 

Chin DV, Tran VT & Le VT (2000) Weedy rice in Vietnam.In: Wild and Weedy Rice in Rice Ecosystems in Asia – A 

Review (Baki, B.B., Chin, D.V. & Mortimer, M., eds.). IRRI, Manila, Philippines, pp. 45-50. 

Croughan TP (1994) Application of tissue culture techniques to the development of herbicide resistant rice. 

Lousiana Agric. 3, 25-26. 

De Datta SK & Baltazar AM (1994) Paper presented at the Conference on Herbicide Use in Asian Rice Production, 

March 28-30, 1994, Stanford University, Stanford, CA, USA, 8p. 

Dekker J (1997) Weed diversity and weed management. Weed Sci. 45, 357-363. 

Fisher AJ & Ramirez A (1993) Red rice (Oryza sativa): competition studies for management decisions. Intl. J. Pest 

Mgmt. 39, 133-138. 

Gealy DR, Mitten DH & Rutger JN (2003) Gene flow between red rice (O. sativa) and herbicide-resistant rice (O. 

sativa): Implications for weed management. Weed Technol. 17, 627-645. 



204

Gealy DR & Estorninos Jr LE (2004) Hybridization between red rice and rice in the U.S.: Implications for gene flow 

and ferality. Abstract: 4 th Intl. Weed Sci. Congr. p. 76. 

Gressel J (2000) Novel controls of millennial weeds. Abstracts 3 rd Intl. Weed Sci. Congr., p.1 

Harlan JR (1969) Evolutionary dynamics of plant domestication. Japanese J. Genetics 44 (suppl.), 337-343. 

Jordan D & Sanders DE (1999) Pest Management. Baton Rouge, LA: Louisiana State University AgCenter, 

Louisiana Rice Production Handbook. Publ. 2321, pp.37-50. 

Madsen KH, Valverde BE & Jensen JE (2002) Risk assessment of herbicide-resistant crops: A Latin American 

perspective using rice (Oryza sativa) as a model. Weed Technol. 16, 216-223. 

MED-Rice Network (2005) Web page: http://www.medrice.unito.it/. Accessed May 2010. 

Menzes VG, da Silva PRF, Carmona R, Rezera F & Mariot CH (1997) Red rice interference on milling yield of 

irrigated rice cultivars. Lavoura Arrozeira 50, 3-6. 

Mislamah AB & Baki BB (1999) The spatio-temporal pattern of distribution of weedy rice accessions in Sungei 

Burong rice granary of Tanjung Karang, Selangor. Proc. 17 th Asian-Pacific Weed Science Society Conference 

1(A), 105-115. 

Noldin JA (1995) Characterization, seed longevity, and herbicide sensitivity of red rice (Oryza sativa L.) ecotypes, 

and red rice control in soyabeans [Glycine max (L.) Merr.]. PhD dissertation, Texas A & M. University, 

College Station, Texas, 218p. 

Noldin JA (2000a) Weedy rices. Abstracts: 3 rd Intl. Weed Sci. Congr., p.246. 

Noldin JA (2000b) In: Wild and Weedy Rice in Rice Ecosystems in Asia – A Review (Baki, B.B., Chin, D.V. & 

Mortimer, M., eds.). IRRI, Manila, Philippines, pp. 21-24. 

Puckridge DW, Chankasom L, Vonsaroj P, Thongbai P & Chinawong S (1988) Effect of tillage and sowing methods 

on control of wild rice. Proc. Intl. Deep Water Rice Workshop (Manila), IRRI, pp. 593-598. 

Riches CR & Valverde BE (2002) Agricultural and biological diversity in Latin America: Implications for 

development, testing, and commercialization of herbicide-resistant crops. Weed Technol. 16, 2000-214. 

Sadohara H, Watanabe O & Rich G (2000) Control of red rice. In: Wild and Weedy Rice in Rice Ecosystems in Asia 

– A Review (Baki, B.B., Chin, D.V. & Mortimer, M., eds.). IRRI, Manila, Philippines, pp. 87-90. 

Sankula S, Braverman MP & Oard JH (1998) Genetic analysis of glufosinate resistance in crosses between 

transformed rice (Oryza sativa) and red rice (Oryza sativa). Weed Technol. 12, 209-214. 

Sato Y (2000) Origin and evolution of wild, weedy, and cultivated rice. In: Wild and Weedy Rice in Rice Ecosystems 

in Asia – A Review (Baki, B.B., Chin, D.V. & Mortimer, M., eds.). IRRI, Manila, Philippines, pp. 7-16. 

Shakirin MM (2009) Descriptive analyses of new biotypes of weedy rice in the Selangor North West Project, 

Malaysia. MSc thesis, University of Malaya, Kuala Lumpur, 245p. 

Shivrain VK, Burgos NR & Rajaguru SN (2004) Cultivar and planting date affect gene flow between Clearfield rice 

and red rice. Abstract: 4 th Intl. Weed Sci. Congr. (Durban), p. 53. 

Valverde BE, Riches CR & Caseley JC (2000) Prevention and Management of Herbicide Resistant Weeds in Rice: 

Experience from Central America with Echinochloa colona. San Jose, Costa Rica. Camara de Insumos 

Agrorecuarios de Costa Rica, 123p. 

Valverde BE (2004) Characteristics, impact and management of weedy rice (Oryza spp.) in rice (O. sativa) in Latin 

America. Abstract: 4 th Intl. Weed Sci. Congr. (Durban), p. 11. 

Vaughan LK, Ottis BV, Prasak-Harvey AM, Bormans CA, Sneller C, Chandler JM & Park WD (2001) Is all red rice 

found in commercial rice really Oryza sativa? Weed Sci. 49, 468-476. 

Vaughan DA & Morishima H (2003) Biosystematics of the Genus Oryza . In: Rice, Oreigin, History, Technology 

and Production (C.W. Smith, R.H. Dilday, eds.). John Wiley & Sons Inc., Hoboken, NJ, pp. 25-65. 

Vonsaroj P (2000) Wild and weedy rice in Thailand. In: Wild and Weedy Rice in Rice Ecosystems in Asia – A 

Review (Baki, B.B., Chin, D.V. & Mortimer, M., eds.). IRRI, Manila, Philippines, pp. 59-68. 

Wahab AH & Suhaimi O (1991) Padi angin, adverse effects and methods of eradication. Teknologi Padi 7, 27-31. 

Watanabe H, Azmi M & Md Zuki I (1996) Ecology of weedy rice (Oryza sativa L.), locally called padi angin, and 

its control strategy. In: Ecology of major weeds and their control in direct seeding rice culture of Malaysia. 

MARDI/MADA/JIRCAS Collaborative Study (1992-1996) (Watanabe, H., Azmi, M. & Md. Zuki, I., eds.), 

pp. 112-166. 

Watanabe H, Vaughan DA &Tomooka N (2000) Weedy rice complex: case studies from Malaysia, Vietnam, and 

Surinam. In: Wild and Weedy Rice in Rice Ecosystems in Asia – A Review (Baki, B.B., Chin, D.V. & 

Mortimer, M., eds.). IRRI, Manila, Philippines, pp. 25-34. 



205

Assessment and attempted eradication of Australian acacias in South Africa as part of an 

EDRR programme 

John R. Wilson 1,2* , Haylee Kaplan 1 , Carlo de Kock 3 , Dickson Mazibuiko 1 , Jason de Smidt 3 , 

Rafael D. Zenni 1 , Ernita van Wyk 2 

1 



2 

South African National Biodiversity Institute, Kirstenbosch National Botanical Gardens, 

Claremont 7735, South Africa. 

3 

Invasive Species Control Unit, South African National Parks, Ground Floor 

Westlake Square, Corner Steenberg Road & Westlake Drive, Cape Town, South Africa 

* Corresponding author, Centre for Invasion Biology, Department of Botany and Zoology, 

Stellenbosch University, Private Bag X1, Matieland 7602, South Africa, 

john.wilson2@gmail.com, Tel: +27 (0)21 808 3408, Fax: +27 (0)21 808 2995 

Introduction 

One of the targets of the initial phase of the South African National Programme 

for Early Detection and Rapid Response (EDRR) of Invasive Alien Plants has 

been introduced wattles (Acacia subgenus Phyllodineae (DC.) Ser.). While 15 

Australian acacias are listed in South African regulations on invasive plants, 

only eleven are widespread. The remaining four species (A. adunca, A. 

implexa, A. paradoxa, A. stricta) have not been investigated in depth, nor has 

there been a concerted or sustained effort to manage these invasive 

populations. In this paper we describe EDRR's involvement in Australian 

Acaica species, in particular: current plans to eradicate A. paradoxa from Table 

Mountain; initial field and risk assessments for A. implexa and A. stricta; and 

surveys to determine the status of other introduced Australian Acacia species. 

Australian Acacia species (or wattles, i.e. Acacia subgenus Phyllodineae) are regarded as a 

model group in invasion biology (Richardson et al., 2011). Management practices around the 

world have focussed on the most widespread invaders, but given the difficulties of long-lived 

persistent seed-banks, preventing or eradicating new invasions before invasions become 

established will be the best strategy (Wilson et al., 2011). 

South Africa is in the process of developing a strategic plan for managing biological 

invasions, and wattles have been used as a test case (van Wilgen et al., 2011). Draft South 

African regulations on invasive alien species (National Environmental Management: 

Biodiversity Act, 2009) lists fifteen species of wattles. Eleven of these have been subjected to 

substantial investigation and are found at several sites throughout the country (Figure 1). These 

species are undisputably invasive (category E according to the scheme proposed by Blackburn et 

al. (2011)); are the subject of on-going management; and are propsed under the draft regulations 

either as category 1b if they are not widely used, or as 2 or 3 if they still provide benefits in some 

instances. 



206

The remaining four species (A. adunca, A. implexa, A. paradoxa, A. stricta) are proposed to 

be listed as category 1a (defined as "requiring compulsory control"). For management purposes 

this is taken to mean they are eradication targets. While A. implexa, A. paradoxa, and A. stricta 

are spread over several hundred hectares (and so are category E), given its restricted distribution, 

A. adunca is taken to be category D1. One more species, not included in the legislation, A. 

viscidula¸ is also recorded as naturalised and spreading from a single site (D1). 

Figure 1 - Frequency distribution of invasive alien plants range sizes in South Africa, with 

fifteen invasive Acacia subgenus Phyllodineae shown in black. Data are from the South 

African Plant Invaders Atlas (accessed 2009). Continental South Africa covers 1944 quarterdegree 

grid cells (QDGCs). The total number of species recorded in SAPIA changes through 

time with taxonomic revisions and new findings, in particular the numbers shown here do not 

reflect the revised results from the EDRR work. 

Another nineteen species of wattle have been introduced to Southern Africa for commercial 

reasons according to a recent review (Poynton, 2009). A further sixty or so species are recorded 

in South African Herbaria, suggesting they have been introduced at some time or other. See 

Richardson et al. (2011) for a compliation of all the species lists. 

In this article we describe the work done by the South African National Programme for Early 

Detection and Rapid Response of Invasive Alien Plants (EDRR) (Ivey et al., this volume) to 

combat wattle invasions. The specific aims are to: a) implement the eradication of A. paradoxa 



207

from Table Mountain through adaptive management; b) provide both initial field and risk 

assessments for A. implexa and A. stricta; and c) determine the status of other introduced 

Australian Acacia species. 

Eradication of A. paradoxa from Table Mountain (Cape Town, SA) 

Acacia paradoxa D.C. (Kangaroo Thorn) is currently restricted in South Africa to around ~3.1 

km 2 on Table Mountain (Devil‘s peak) (Moore et al., 2011). The current population is thought to 

be the result of a few plants initially introduced as a curiosity around the end of the nineteenth 

century, followed by a long history of neglect (Zenni et al., 2009). Alien plant clearing 

operations started targetting the plant in the mid-1990s. While the intention of the recent 

management efforts was to eradicate the population, the clearing until now can be categorised as 

sporadic and partial, focussing mostly on the largest and presumably oldest plants. The first 

detailed survey of the population was conducted in 2008 as part of a student project (Zenni et al., 

2009), and since then targetted efforts have been co-ordinated by EDRR to ensure the population 

is eradicated. 

General alien clearing operations in the affected area (based on figures from 2009/2010) cost 

around 400–600 Rands. ha -1 , with the return time in any one location approximately 3–5 years. 

However, this is insufficient to prevent plants producing seeds, particularly as one year old plants 

can possibly set seed and plants over 2m tall are missed during the clearing. In an area of 45 000 

m 2 evaluated 3 years after general alien clearing operations, around 1 000 A. paradoxa plants 

were found, most showing signs of reproduction (Zenni et al., 2009). 

Fortunately, the population does not appear to have spread far from the initial point of 

introduction, and the seed-bank is confined almost exclusively to below the canopy. If annual 

search-and-destroy operations systematical survey the affected area during the flowering season 

(i.e. August–October) (Fig. 2), it is likely that seed-set can be prevented. Indeed, a recent 

decision analysis suggested that the optimal management goal for this population is eradication 

(Moore et al., 2011). 

After the first year of clearing in response to the report of Zenni et al. (2009) , a wild-fire in 

early 2009 went through much of the affected area. This allowed an assessment of the effect of 

fire on seed germination. In both field assessments and lab trials, fire stimulated up to 90% seed 

germination compared to an average of around 10% in normal conditions (D. Mazibuko, 

unpublished data). Despite the fact that in the dense areas there was 100% cover with A. 

paradoxa following the fire, there was a substaintial regrowth of species other than A. paradoxa. 

This new species-specific approach that was not confined to previous operating plans was one of 

the reasons for developing an EDRR (Ivey et al., this volume). 



208

a) 

b) 

Figure 2 - Example of surveying work on Acacia paradoxa on Table Mountain in December 

2009. a) physical area surveyed; b) track-lines recorded and plotted on Google Earth. Each 

icon represents the location of an Acacia paradoxa that was found and treated. The survey 

consisted of teams of three or four, walking up, then down with one of the surveyers carrying 

a GPS. So at least four people walking parallel to each other will have surveyed in the gap 

between tracks (see Zenni et al., 2009 for more details). 

The project is now in a follow-up phase involving further search-and-destroy surveys and 

pulling of seedlings that have emerged following the Vredehoek fire in May 2009. In 2010 the 

unburnt areas (1.45 km 2 ), were resurveyed costing 64 000 Rands, and about a hundred adult 



209

plants were found (not found on previous surveys). Later in the year and in the start of 2011, in 

the burnt section over 600,000 seedlings were hand-pulled on a contract costing 400 000 Rands. 

As such the exercise is much more expensive than general clearing operations (which will still 

continue in the area separate to the A. paradoxa work). Initial estimates suggest that working in 

groups of 2–4 people, each person can cover 1–2 ha per day (so a total requirement of around 

200 person field days per year). However, this approach is estimated to be much more costeffective 

than if either no action is taken, or containment is attempted (Moore et al., 2011). The 

total cost estimate if control is successful is 5.4 million Rands spread over 20 years. 

In addition to the walked search-and-destroy surveys (Fig. 2), areas immediately adjacent to 

the park will be surveyed (EDRR provides a more flexibile mandate than if the process was 

controlled solely by South African National Parks); and in steep areas within Table Mountain 

National Park, specifically trained and equipped "high angle teams" will be used, and plants 

treated as before. 

As for most of the invasive Australian Acacias in South Africa (Richardson & Kluge, 2008), 

A. paradoxa has a significant long-lived seed-bank of >1000 seeds m -2 in places, and our concern 

is that in dense areas, the seed-bank will persist for decades. Given the fact that Table Mountain 

National Park is a World Heritage Site, alien clearing operations are likely to be a part of land 

management for many years to come. Nonetheless, efforts to reduce the seed-bank would be 

advisable. Unfortunately, the infested site is very close to Cape Town (see Figure 1), and as such 

the requirements for allowing fires in this area are stringent. The main future steps in the 

eradication will be to assess the success and control of current practices and assess the likely 

benefits of using different methods to reduce the seed-bank. 

Initial field and risk assessments for A. implexa and A. stricta 

The initial assessment of A. implexa was started in 2009, and was completed in early 2011 

confirming the view that this species should also be an eradication target 

(Kaplan et al. in review South African Journal of Botany). Three populations of A. implexa have 

been identified, mapped, and studied as part of a student project funded by EDRR. The survey 

found approximately 30 000 A. implexa individuals within a total invaded area of 6 km 2 across 

the three sites. While A. implexa produces a prodigious amount of seed, it appears not to have 

spread widely yet (perhaps through poor dispersal and high seed mortality), although it is 

beginning to spread along one water-course. Control is problematic given its strong ability to 

sucker, but general clearing operations (co-ordinated but not managed by EDRR) are on-going. 

The exact delimitation of the species in South Africa is not certain as the species is difficult 

visually to separate from Acacia melanoxylon R.Br. in W.T.Aiton. Indeed, several new reports 

of sightings have subsequent been confirmed as A. melanoxylon. We have distributed 

identification leaflets asking for new sightings, and if many new reports are confirmed, then the 

project will need to be reassessed. But given the relatively slow spread, but the threat it poses to 

biodiversity, it will remain an eradication target for the present. 

Acacia stricta (Andrews) Willd. is only known from a few populations scattered through the 

Kynsna and Wilderness areas of the Southern Cape. Much of the population appears to be 



210

situated close to road-sides in pine plantations, though it is reaching high densities in places, and 

is again a prolific seed producer. It is unclear how it reached the area, but has been there for at 

least 15 years, perhaps being spread by vehicles or road resurfacing work. Control of mature 

plants appears to be relatively straight-forward, although the seed-bank may represent a major 

challenge for eradication, and certainly the populations along the major highway (the N2) were 

of concern regarding its potential spread. 

A thorough survey of the area in September 2010 found eight populations of A. stricta and a 

total of ~ 20 000 plants, all of which occured on plantation land. The infestations straddle 

various land-owners and management areas (in particular the Mountain to Ocean Forestry 

Company). EDRR facilitated a meeting of all stakeholders involved in May 2011, and the group 

are developing a joint management plan. This is a good example where EDRR can act as an 

independent co-ordinator to ensure that appropriate control occurs wherever plants are found (see 

paper by Ivey et al., this volume). 

Surveys of other introduced Australian Acacia species 

Records of Australian acacias in the Southern African Plant Invaders Atlas as well as records 

in South African Herbaria are being collated and followed up. Acacia adunca Cunn. ex Don is 

currently known to have naturalised in only one site in South Africa, ―Bien Donné‖ 

Experimental Farm in the Franschoek Valley, and the population is being assessed. However, it 

has not spread widely and is not an immediate priority for eradication. 

Several other species have also been found. Acacia viscidula Benth. is invading Newlands 

Forest on the slopes of Table Mountain in Cape Town, and a few plants of Acacia ulicifolia 

(Salisb.) Court and Acacia retinoides Schldl. have naturalised at Tokai Arboretum in Cape Town 

(i.e. category C3). Reports of Acacia fimbriata Cunn. ex Don in Grahamstown have been 

followed up, but no plants were found (potentially category A2). We still need to confirm if a 

reported naturalised population of A. cultriformis Cunn. ex Don from Ladybrand exists. There 

are also arguable two species that are planted in some numbers but are not recorded as invasive 

Acacia pendula Cunn. ex Don and Acacia floribunda (Vent.) Willd. (potentially category B2), 

but again more work is required to confirm their status as not naturalised. 

Conclusions 

Given the number and diversity of Australian acacias introduced to South Africa, they 

represent an excellent test case both for general theories of invasivenss and for our ability to 

conduct eradications. The long history of introduction and plantings means that there is a high 

possibility for many species that are currently at low density to become invasive in later years, 

and the long-lived seed bank represents a challenge for control. 

We would, however, conclude that specific EDRR type projects are warranted on Australian 

Acacia species as: they allow the flexibility to look at infestations across administrative and 

management boundaries; they provide continuity of funding; and EDRR provides the focus 

required for eradication. The last point is particularly important given the number of invasive 

Australian Acacia species that require general management. 



211


This work was funded by South Africa‘s Working for Water Programme (WfW) of the 

Department of Water and Environmental Affairs, with support from the DST-NRF Centre of 

Excellence for Invasion Biology. The work would not have been possible without numerous field 

assistants and clearing teams, we would particularly like to thank Agnes Sogiba and Douglas 

Euston-Brown. We would also like to thank Chris Botes of SAN Parks for bringing several new 

sightings to our attention. 

References 

Blackburn TM, Pyšek P, Bacher S, Carlton JT, Duncan RP, Jarošìk V, Wilson JRU & Richardson DM (2011) A 

proposed unified framework for biological invasions. Trends in Ecology & Evolution 26, 333–339. 

Moore JL, Runge MC, Webber BL & Wilson JRU (2011) Contain or eradicate? Optimising the goal of managing 

Australian acacia invasions in the face of uncertainty. Diversity and Distributions 17, DOI: 10.1111/j.1472- 

4642.2011.00809.x. 

National Environmental Management: Biodiversity Act (2009) Draft Alien and Invasive Regulations (eds 

Department of Environmental Affairs and Tourism). Government Gazette, Pretoria, South Africa. 

Poynton RJ (2009) Tree planting in southern Africa: vol. 3 other genera. Department of Agriculture, Forestry, and 

Fisheries. 

Richardson DM, Carruthers J, Hui C, Impson FAC, Miller J, Robertson MP, Rouget M, le Roux JJ & Wilson JRU 

(2011) Human-mediated introductions of Australian acacias—a global experiment in biogeography. Diversity 

and Distributions 17, (in press no DOI yet). 


invasiveness and options for management. Perspectives in Plant Ecology Evolution and Systematics 10, 161- 

177. 

Southern African Plant Invaders Atlas, http://www.agis.agric.za/wip/ [Accessed 2009]. ARC-Plant Protection 

Research Institute, Pretoria. 

van Wilgen BW, Dyer C, Hoffmann JH, Ivey P, Le Maitre DC, Richardson DM, Rouget M, Wannenburgh A & 

Wilson JRU (2011) A strategic approach to the integrated management of Australian Acacia species in South 

Africa. Diversity and Distributions 17, DOI: 10.1111/j.1472-4642.2011.00785.x. 

Wilson JRU, Gairifo C, Gibson MR, Arianoutsou M, Bakar BB, Baret S, Celesti-Grapow L, Dufour-Dror JM, 

Kueffer C, Kull CA, Hoffmann JH, Impson FAC, Loope LL, Marchante E, Marchante H, Moore JL, Murphy 

D, Pauchard A, Tassin J, Witt A, Zenni RD & Richardson DM (2011) Risk assessment, eradication, 

containment, and biological control: global efforts to manage Australian acacias before they become 

widespread invaders. Diversity and Distributions 17, DOI: 10.1111/j.1472-4642.2011.00815.x. 

Zenni R, Wilson JRU, Le Roux JJ & Richardson DM (2009) Evaluating the invasiveness of Acacia paradoxa in 

South Africa. South African Journal of Botany 75, 485–496. 



212

The value of context in early detection and rapid response decisions: Melaleuca invasions in 

South Africa 

Ernita van Wyk 1 and Llewellyn Jacobs 2 and John Wilson 1,3 

1 

South African National Biodiversity Institute. P/Bag X7. Claremont 3357. Cape Town. South 

Africa 

2 

CapeNature. Scientific Services. Private Bag X5014. Stellenbosch 7599. South Africa 

3 



Introduction 

In the context of the South African Early Detection and Rapid Response 

Programme, decisions around risk and response have to be made as quickly as 

possible using available data. In an adaptive management framework, control is 

coupled with the collection of data on e.g. history of species behaviour 

elsewhere, presence of traits associated with invasiveness and spatial 

distribution at known sites. As data collection proceeds, estimates of risk of 

spread are revised. This paper uses an example of Melaleuca invasions in a 

mediterranean ecosystem (fynbos) in the Western Cape, South Africa as an 

illustration of how risk and response should be updated as more information 

becomes available. We describe how contextual insights augment the 

fundamental understanding of the invasion system. We show how the 

consideration of aspects such as expected ease of effort, population data, 

history of introduction, and site history all enrich the initial assessments made 

on the basis invasiveness elsewhere and species traits. Such considerations are 

expected to enhance understanding of the broader system variables that 

influence risk assessment of invasive species within mediterranean fynbos. We 

produce a conceptual framework to illustrate this finding. 

Most governments and societies endorse the allocation of resources to the protection of 

biological diversity. They also support resource allocation to reduce the risks associated with 

threats to biodiversity such as those posed by invasive alien organisms (McGeoch et al., 2010). 

However, the resources to address the invasive alien problem are limited and must be prioritised 

in order to leverage acceptability of results for any given investment. Within the South African 

Early Detection and Rapid Response Programme (EDRR) context (see Ivey et al. this issue), the 

focus of resource allocation is on species that have naturalised but are not yet widespread. Given 

a set budget and the large number of potential targets, only a few species can be prioritised. Such 

prioritisation needs to consider both the invasion risk posed and the ease with which goals can be 

achieved given the management context (Moore, 2010). Because such risk decisions are intended 

to direct human behaviours and financial resources, approaches to the assessment of invasion 

risk is a well debated and much researched topic. 

213 


2 nd According to Giampietro (2004), ‗risk‘ is a situation in which it is possible to assign a 

distribution of probabilities to a given set of possible outcomes. The assessment of risk can be 

based on the knowledge of probability distribution over a known set of possible outcomes 


obtained using validated inferential models. Alternatively, risk can be determined in terms of 

agreed-upon subjective probabilities. However, Giampietro (2004) is quick to remind us of the 

difference between a complex natural system and the scientific representation of that system, the 

latter being a construct that confines our efforts to understand the system to what we believe to 

be relevant attributes of the system. In this sense, a risk assessment is a representation of the 

complex natural system based on criteria believed to be most influential in determining the 

invasive potential of a species. Typically, invasive alien risk assessments are based on biological, 

ecological and biogeographical criteria, the measures of which are used to populate risk models. 

Commonly used criteria include climate and distribution, undesirable traits, weedy relatives and 

weediness elsewhere (Pheloung et al., 1999; Nel et al., 2004 and Mgidi et al., 2007; Brunel et 

al., 2010). Even in cases where risk and prioritisations are based on subjective expert agreement 

(Roura-Pascual et al., 2009) and where non-biological traits are incorporated into risk models 

(e.g. Burns, 2006) the derivation of risk tends to be mechanistic rather than aimed at developing 

an interpretive understanding of the wider ecological and the even wider social-ecological 

system (Stirling et al., 2007). 

In this paper, we examine an example from invasive melaleucas in the South African 

mediterranean climate region. Our observations of populations of two exotic Melaleuca species 

with apparently similar residence time, but which have shown surprisingly ‗uncharacteristic‘ 

spread rates, have provided an opportunity to interrogate our assumptions about how we 

determine invasive potential and risk and ultimately the decisions we have made in the EDRR 

Programme. We use this example to illustrate how contextual information can enrich risk-based 

decision-making and the allocation of public resources. Based on these insights, we develop a 

conceptual framework that prompts interpretive thinking about the larger system beyond what 

we can know about the biology and ecology of the species of interest. Although some literature 

on biological invasions suggest a more holistic approach to understanding the invasion system 

(see Lockwood et al., 2007; Simberloff, 2009), none of these attempt explicit conceptual 

advances in this direction. This paper presents an example from the Melaleuca invasions in 

South Africa to illustrate how contextual information contributes to risk and decision-making. 

Approach 

We use a grounded approach (Strauss & Corbin, 1998) to reflect on and document some key 

considerations that have affected our understanding of the system of selected Melaleuca 

invasions in South Africa and which have encouraged us to revise our response. The points made 

are not intended to be exhaustive, but rather aim to illustrate the value of incorporating 

contextual aspects into an understanding of an invasion system. 

Melaleuca invasions in South Africa 

Members of the Melaleuca genus have long been popular garden and urban street ornamentals 

in South Africa, indeed one of the most popular varieties takes its name from the financial 

capital: hybrid Melaleuca bracteata var. "Johannesburg Gold". None of the species have been 

widely cultivated in the country although M. alternifolia is planted for its medicinal and culinary 

uses. Historically, melaleucas were also common features of botanic gardens. Despite apparent 

opportunities for spread, reports of naturalisation and invasiveness are relatively rare: the only 



214

ecords prior to the study described here are of M. hypericifolia and M. wilsonii naturalising on 

the Cape Peninsula and from a flower farm in the Western Cape respectively; and M. 

quinquenervia recruiting at the Tokai arboretum in Cape Town (source: SAPIA database). 

First records and initial risk assessment 

During 2007 and 2009 respectively, staff of a provincial conservation agency (CapeNature) 

discovered two relatively small, naturalising populations of M. ericifolia and M. quinquenervia 

on and close to the Waterval Nature Reserve near Tulbagh in the mediterranean climate region of 

the Western Cape. The Tulbagh sightings mentioned here were the first records of major 

invasion events by melaleucas into natural areas in South Africa. Conservation staff initially 

required confirmation of the species identity, in particular whether it was native or alien to the 

region. In May 2009, this information was passed on to the newly formed national EDRR 

Programme which operates as part of the South African National Biodiversity Institute (SANBI). 

As EDRR was embarking on a 3-year pilot phase, the melaleuca discovery at Waterval presented 

an excellent opportunity for SANBI-EDRR, CapeNature and others to form a partnership to 

better understand and manage these invasions. 

The discovery of M. quinquenervia in South Africa, a few months after the discovery of M. 

ericifolia, was especially interesting because of the extensive and well documented M. 

quinquenervia invasions in the Florida Everglades and the comprehensive and costly U.S. 

investment spanning several decades (Laroche & Ferriter, 1992; Laroche, 1999; Pratt et al., 

2003; Dray et al., 2006). This example is well known in the invasion ecology and management 

circles and M. quinquenervia has been listed as one of the 100 worst invasive alien organisms 

globally (Lowe et al., 2000). In contrast, we have not been able to source any scientific records 

of M. ericifolia being invasive, apart from weediness in south-eastern Australia (Global 

Compendium of Weeds). However, there is much known about the ecology of M. ericifolia 

because it is used as an indicator of wetland dynamics in its native range in Australia (Robinson, 

2007; Salter et al., 2010). Both M. quinquenervia and M. ericifolia prefer growing in seasonal 

wetlands (Hamilton-Brown et al., 2009) suggesting that these habitats are considered the most at 

risk. Figure 1 shows a mind-map indicating how species knowledge and invasiveness elsewhere 

were the factors that initially influenced EDRR perception of risk. 

As per convention, the EDRR team set out to measure selected variables that would provide 

us with baseline data to characterise the M. quinquenervia and M. ericifolia populations. In a 

destructive sampling exercise, we recorded plant height, width, basal stem diameter, number of 

growth rings (age) where possible and the exact geographical coordinate of each live stem. The 

information gathered allowed us to characterise each population precisely such that we are able 

to quantitatively monitor population response to treatment. The information also allows us to 

model potential rate of spread. 

We furthermore spent many hours at the respective sites and beyond, observing the plants, 

debating variables of interest and conversing with various land managers about the Melaleuca 

populations. 



215

Species knowlesge 

e.g. M. ericifolia 

ecology well 

studied 

Invasiveness and impacts 

elsewhere 

e.g. M. quinquenervia 

well studied & control 

techniques refined 

Habitat 

requirements 

Figure 1 - A mind-map showing the factors that initially influenced EDRR perception of risk. 

Melaleuca quinquenervia was introduced into the U.S. more than a dozen times for a variety 

of reasons and in large numbers since 1815 and now covers approximately 200 000 ha of 

wetlands in southern Florida (Dray et al., 2006). Its invasive tendencies were recorded from 

around the 1920s. The species is well adapted to growth in both tropical and temperate climates, 

indicating that it may be adapted to invade all areas of South Africa apart from the driest interior. 

Large-scale and intensive efforts by the U.S. government to manage M. quinquenervia in Florida 

began in 1988 (Laroche, 1999). As part of their efforts to control the species, they have refined 

herbicide application techniques and have isolated the active ingredients most effective against 

the plant. In addition, the U.S. task team for M. quinquenervia have made their lessons and 

experience available on a website (http://tame.ifas.ufl.edu/) which has greatly facilitated fasttracked 

learning by the South African EDRR team. In many ways, the well-researched and wellpublicised 

U.S. example has had the effect of raising the risk perception of the species in South 

Africa, improving our readiness to respond to the problem. Knowing which herbicides are most 

effective has also been beneficial in response planning. These aspects show that being able to 

learn from others‘ experiences improves the likelihood of preventing the spread of a species and 

providing a robust motivation for allocating resources to a project. Figure 2 shows how our 

initial perception of risk was increasingly enhanced by new information and notably by 

information that was not related to the biology of the species. 

Initial EDRR field observations and measurements 

Actual distribution 

Preliminary 

estimation of risk 

Response planning, 

prioritisation, resource 

allocation and action 

One of the first intriguing observations was that the naturalised M. quinquenervia population 

near Tulbagh was much smaller than that of M. ericifolia (0.02 km 2 vs. > 0.4 km 2 ). Preliminary 

estimates of age ring counts suggested that the M. ericifolia population currently being removed 

is aged between 9 and 11 years. The M. ericifolia population residence time may be older, since 

we found 3 large plant remains of what would have been M. ericifolia mother trees, amongst the 

live plants in an area which is likely the source of the infestation. Stems in the M. quinquenervia 



216

populations were too soft and papery to produce age rings, but some had basal stem diameters of 

up to 23 cm. From observations of large charred plants, the population survived the most recent 

fire in 1988 (source: CapeNature fire records) and thus the M. quinquenervia population must be 

at least 22 years old. Based on these observations, M. ericifolia seems to have been released from 

a lag phase and has spread across an area at least 50 times the size of the M. quinquenervia 

population. In Florida, M. quinquenervia thrives in permanent wetlands in subtropical climate 

(similar to its native Australian climate) whereas in Tulbagh M. quinquenervia occurs in a 

seasonal wetland is subject to a typical mediteranean climate. Consequently, at this stage, we are 

regarding M. quinquenervia as an eradication possibility whilst eradication potential for M. 

ericifolia needs further assessment. The initial expectation was therefore that M. quinquenervia 

represented a much large threat, and that perhaps M. ericifolia was of low risk, but that for M. 

quinquenervia much management information was readily available (See Figure 2). 

Stage Melaleuca 

ericifolia 

First report of 

invasiveness 

Learning 

from 

invasions 

elsewhere 

Field 

observations 

and 

measurements 

Understanding 

the context 

LOW- 

MEDIUM 

LOW- 

MEDIUM 

Melaleuca 

quinquenervia 

Not initially 

reported 

Notes Uncertainty 

Initial reports of an invasion from 

CapeNature (M. ericifolia) 

indicated a species to be 

considered. Only on the first site 

visit was another species 

naturalising mentioned. 

VERY HIGH Based on experience in other 

countires, M. quinquenervia was 

immediately prioritised as of 

concern, but there was no 

indication M. ericifolia was 

particularly widespread. 

HIGH HIGH Mapping exercise quickly showed 

that M. ericifolia occupied a 

substantial range at increasing 

densities. With a small range 

there was little indication that M. 

quinquenervia had spread far. 

HIGH HIGH By raising awareness new 

populations of M. ericifolia were 

identified. Understanding how 

and why the species were 

introduced was essential to 

determining where to look, 

though given the precautionary 

principle the risk assessments 

were not changed. 



Diversity of 

information 

sources 

Figure 2 - Qualitative risk perceptions were updated during the course of the ongoing 

investigation. These risk perceptions were combined with management context (e.g. ease of 

eradication) to determine the response. 

The Waterval Nature Reserve staff manages a number of mountain catchments in the area for 

biodiversity protection and water conservation. This conservation area is fringed by agricultural 

land and plantations. Because of poor soils and insufficient rainfall, the state owned commercial 

217

forestry industry in the Western Cape has embarked on a strategy to reduce its activities in areas 

where wood cannot be grown viably. As forestry decommissioned some of their plantations, 

these areas were returned to conservation authorities for rehabilitation. Both the M. 

quinquenervia and M. ericifolia populations are found on previously forested sites, with the 

melaleucas emerging after eucalypt and pine trees were felled and not replanted. During 2009, 

the staff at the Kluitjieskraal forestry office learnt of the melaleucas at Waterval, and approached 

the EDRR Programme, indicating that M. ericifolia has become widespread in the understory of 

the plantation forests managed by them. A site visit confirmed this and indicated that the M. 

ericifolia population is much larger than we had initially thought. At first, the known population 

of M. ericifolia covered approximately 40ha. A further 40ha was discovered (Kluitjieskraal 

wetland) and since plants were found to be relatively widespread in the plantation forest 

understory, we currently estimate the total area under M. ericifolia to be greater than 100ha 

(1km 2 ). Importantly, it prompted us to understand more about a possible linkage between 

commercial forestry practices and the Melaleuca populations relevant to EDRR. In terms of risk 

perception, even though risk remains high (unchanged), awareness of new populations changes 

the management context and the perception of ‗ease of eradication‘ decreases (See Figure 2). 

Making sense of context 

History of introduction 

Given that the Kluitjieskraal forestry station and its associated nursery are the second oldest in 

the country (established in 1877; MTO Forestry, pers. comm.), we considered the possibility that 

Melaleuca seeds had arrived to be grown as ornamentals. However, a recent review of tree 

plantings in Southern Africa (Poynton, 2009) does not mention any introductions of Melaleucas 

for commercial reasons. We are busy investigating the Kluitjieskraal import and nursery 

records, but as yet there is no direct evidence of deliberate introduction, and as such introduction 

as a soil contaminant is a possibility. We also spent some time browsing the area in and around 

the Kluitjieskraal estate. We found other bottlebrush species (e.g. Callistemon rigidis and 

Melaleuca styphellioides) beginning to naturalise in the Kluitjieskraal wetland. This would 

support the notion that there was a historical collection of imported Myrtaceae in the area, but 

again this remains to be seen. In either case, plants appear to have established and spread as a 

result of the ideal seasonal wetland conditions and the removal of competition by the felling of 

commercial eucalyptus and pine species. As a consequence, EDRR staff decided to direct their 

surveillance strategies towards forest plantations and conservation areas that had previously been 

forested, to determine the true extent of M. ericifolia populations. 

Ease of eradication 

Having the benefit of the U.S. experience, together with the small size of the M. 

quinquenervia population in South Africa presents an attractive and cost-effective eradication 

opportunity. Costs for the South African project so far (based on 12 months of effort) amounts to 

R15 000 (Assuming a cost of R120 per person day, accommodation and meals, equipment and 

transport since July 2009). An estimation of future costs (the next 15-20 years) still needs to be 

made. In comparison, the U.S. spent US$ 25 million between 1988 and 1998 and they estimated 

that the cost of no action in the Florida Everglades would be US$ 161 million per year in lost 

revenue (Laroche, 1999). As with the American control project, the South African project enjoys 



218

good political and financial support as well as the benefit of effective collaborations to support 

both research and management. These factors are all in line with Dan Simberloff‘s five key 

requirements for likely success in eradication (Simberloff, 2009): (1) early detection and quick 

action, (2) sufficient resources for the full duration of the project, (3) a dedicated authority to 

drive agency co-operation, (4) sufficient information about the species, and (5) enthusiastic 

project leaders. 

In contrast, the feasiblitiy of eradicating M. ericifolia has yet to be determined, since the 

population is larger and more scattered widespread than initially estimated and our confidence in 

knowing the extent of the population is still low. 

Precautionary principle 

For both Melaleuca species we invoke the ‗precautionary principle‘, accepting that we should 

not wait for impacts to be measurable before we act (Blossey et al, 2001; Simberloff, 2003) and 

while there is political and financial backing, to commit to the best possible efforts for 

eradication and containment. For M. quinquenervia, even though its spread seems currently to be 

very limited, our risk perception is heightened by the commonly used risk criterion of 

‗invasiveness elsewhere‘ and thus choose to act to caution against its spread. In contrast, we 

cannot lean on the same criterion for M. ericifolia. However for this species, we still use the 

precautionary principle and allocate resources to control, since our perception of risk for this 

species is triggered by our on-site observations that it is spreading successfully across the 

landscape. 

A conceptual framework 

We considered the contextual aspects discussed and realised that have substantially influenced 

our perception of risk, and therefore planning and actions. Figure 3 (see appendix) presents a 

mind-map of how we see contextual information contributing to risk estimation and response 

management of Melaleuca invasions in South Africa. 

Discussion 

Our findings highlight several lessons for EDRR. Firstly, we show that risk-criteria 

commonly used such as invasiveness or weediness elsewhere, are not perfectly predictive. Even 

though in the cases shown we would be prudent to attach high risk to M. quinquenervia, on-site 

observations for M. ericifolia suggest that we should attach as much risk to this species as to M. 

quinquenervia and that this should be reflected in response planning and action. This finding 

highlights the need to update preliminary risk assessments with site- and context-specific 

information. Our findings also show that decisions in terms of response planning and action are 

as much influenced by opportunity as risk. In other words, decision-making is not purely riskbased. 

Ease of eradication and sustained political will provide two points that affect how we 

motivate for species prioritisation and resource allocation in EDRR. These factors also highlight 

the limitation of population data as it can provide only a partial insight into risk estimation and 

response planning that will lead to likely success. 



219

In general our findings have led us to expand our understanding of the drivers of risk for the 

two Melaleuca species and we have used these insights to understand how we have rationalised 

our adjustments of risk perception for the two species. We also found that contextual information 

can affect how we think about, and possibly lead us to adjust our responses. Directly measured 

population data provide quantitative information about the attributes of the population and built 

into a model, can produce predictive indications of risk of future spread. This provides essential 

base-line against which management efficacy needs to be measured, and is necessary to convince 

interested and affected parties that action is required. But, these parameters (reflecting the 

‗current state‘ of invasion) are symptomatic of underlying drivers of the invasion system and the 

social system that is both the cause and the response mechanism. We suggest that contextual 

information provides us with possible key driving variables that aid us in developing a more 

fundamental understanding of the system and the ‗problem‘ or ‗symptom‘ that we see (Senge et 

al., 2008). In taking this approach, we recall Giampietro‘s point by attempting to develop a more 

comprehensive and more fundamental representation of the system we are interested in. A good 

example from the South African melaleucas is the link with plantation forests in the area as a 

possible source of infestation. Importantly, this has led us to consider directing resources to 

future surveillance strategies to plantation forests and recovering natural areas that were 

previously under plantation. It has also drawn our attention to the forest industry as an important 

collaborator in our EDRR efforts. In the end, we affirmed both species to be high-risk 

candidates, but we have gained a better understanding of the underlying drivers of the patterns of 

invasion. 

An interesting point from our experience with the melaleucas is that the new contextual 

insights did not come about in an anticipated manner. Instead, the new information emerged as a 

result of planned as well as unplanned collaborations between various agencies. For EDRR, this 

indicates the importance of collaborative links in the promotion of information sharing and the 

generation of new insights. It also means that gathering contextual insights typically cannot be 

done in a mechanistic way, but are emergent properties of a collaborative knowledge creation 

system. The performance of EDRR staff in South Africa is in part evaluated on their 

collaborations, with the intention to motivate staff to develop inter-organisational linkages. 

In summary, a broader and more context-based understanding of the invasion system has 

prompted us to inform our risk assessment with a more diverse knowledge contribution. The 

emergence of natural resource approaches such as place-based management (Manuel-Navarrete 

et al., 2006) and implementation-oriented research (Bammer, 2005) signify a recognition of 

place-based insights and diverse knowledge contributions to an improved understanding of 

whole system functioning. The melaleuca example indicates the importance of both human and 

natural history in an EDRR context (see Dayton & Sala, 2001). The challenge for EDRR will be 

to ensure these aspects are meaningfully combined in response planning and action. The 

Melaleuca species project in South Africa is in its infancy and many challenges await. However, 

we are encouraged by an approach that is more sensitive to context and believe that 

incorporating these aspects into a more fundamental understanding of the invasion system will 

promote more effective responses. 



220


We gratefully acknowledge our partners, MTO Forestry and CapeNature staff at Waterval. We 

also kindly acknowledge our funder, the natural Resource Management Programme of the 

Department of Environmental Affairs. 

References 

Bammer G (2005) Integration and implementation sciences: building a new specialisation. Ecology and Society 

10(2), 6. 

Blossey B, Skinner LC & Taylor J (2001) Impact and management of purple loosestrife (Lythrum salicaria) in 

North America. Biodiversity and Conservation 10, 1787-1807. 

Brunel S, Schrader G, Brundu G & Fried G (2010) Emerging invasive alien plants for the Mediterranean basin. 


Burns J (2006) Relatedness and environment affect traits associated with invasive and non-invasive introduced 

Commelinaceae. Ecological Applications 16(4),1367-1376. 

Craven LA (2006) New combinations in Melaleuca for Australian species of Callistemon (Myrtaceae). Novon 16, 

468-475. 

Dayton PK & Sala E (2001) Natural history: the sense of wonder, creativity and progress in ecology. Scientia 

Marina 65(2), 199-206. 

Dray FA, Bennet BC & Center TD (2006) Invasion history of Melaleuca quinquenervia (Cav.) S.T. Blake in 

Florida. Castanea 71(3), 210-225. 

Giampietro M (2004) Multi-scale integrated analysis of agroecosystems. CRC Press. Florida. 

Global Compendium of Weeds. Accessed 20 July 2011: http://www.hear.org/gcw/. AgWest and the Hawaiian 

Ecosystems at Risk project. 

Hamilton-Brown S, Boon PI, Raulings E, Morris K & Robinson R (2009) Aerial seed storage in Melaleuca 

ericifolia Sm. (Swamp paperbark): environmental triggers for seed release. Hydrobiologia 620, 121-133. 

Laroche FB (1999) Melaleuca Management Plan. Ten years of successful Melaleuca management in Florida, 1988- 

1998. Florida Exotic Pest Plant Council. 

Laroche FB & Ferriter AP (1992) The rate of expansion of Melaleuca in South Florida. Journal of Aquatic Plant 

Management 30, 62-65. 

Lockwood JL, Hoopes MF & Marchetti M (2007) Invasion Ecology. Blackwell Publishing. Massachusetts. 

Lowe S, Browne M, Boudjelas S & De Poorter M (2000) 100 of the World’s Worst Invasive Alien Species. A 

selection from the Global Invasive Species Database. Published by the Invasive Species Specialist Group 

(ISSG) a specialist group of the Species Survival Commission of the World Conservation Union. 

Manuel-Navarrete D, Slocombe S & Mitchell B (2006) Science for place-based socioecological management: 

Lessons from the Maya Forest (Chiapas and Petén). Ecology and Society 11(1), 8. 

McGeoch MA, Butchart S HM, Spear D, Marais E, Kleynhans EJ, Symes A, Chanson J & Hoffmann M (2010) 

Global indicators of biological invasion: species numbers, biodiversity impact and policy responses. 

Diversity and Distributions 16, 95-108. 

Mgidi TN, Le Maitre DC, Schonegevel L, Nel JL, Rouget M & Richardson DM (2007) Alien plant invasions – 

incorporating emerging invaders in regional prioritization: a pragmatic approach for southern Africa. Journal 

of Environmental Management 84, 173-187. 

Moore JL, Rout TM, Hauser CE, Moro D, Jones M, Wilcox C & Possingham HP (2010) Protecting islands from 

pest invasion: optimal allocation of biosecurity resources between quarantine and surveillance. Biological 

Conservation 143, 1068-1078. 

Nel JL, Richardson DM, Rouget M, Mgidi TM, Mdezeke N, Le Maitre DC, van Wilgen BW, Schonegevel L, 

Henderson L & Neser S (2004) A proposed classification of invasive alien plant species in South Africa: 

towards prioritising species and areas for management action. South African Journal of Science 100, 53-64. 

Pheloung PC, Williams PA & Halloy SR (1999) A weed risk assessment model for use as a biosecurity tool 

evaluating plant introductions. Journal of Environmental Management 57, 239-251. 

Poynton R J (2009) Tree planting in Southern Africa: vol. 3 Other Genera. Department of Agriculture, Forestry, and 

Fisheries. 

Pratt PD, Slone DH, Rayamajhi MB, Van TK & Center TD (2003) Geographic distribution and dispersal rate of 

Oxyops vitiosa (Coleoptera: Curculionidae), a biological control agent of the invasive tree Melaleuca 

quinquenervia in South Florida. Environmental Entomology 32(2), 397-406. 



221

Robinson R (2007) Regeneration mechanisms in swamp paperbark (Melaleuca ericifolia Sm.) and their implications 

for wetland rehabilitation. PhD thesis. Victoria University, St. Albans, Victoria, Australia. 

Roura-Pascual N, Richardson DM, Krug RM, Brown A, Chapman RA, Forsyth GG, Le Maitre DC, Robertson MP, 

Stafford L, van Wilgen BW, Wannenberg A & Wessels N (2009) Ecology and management of alien plant 

invasions in South African fynbos: accommodating key complexities in objective decision making. 

Biological Conservation 142(8), 1595-1604. 

Salter J, Morris K, Reed J & P.I. Boon (2010) Impact of long-term, saline flooding on condition and reproduction of 

the clonal wetland tree Melaleuca ericifolia (Myrtaceae). Plant Ecology 206, 41-57. 

South African Plant Invader Atlas (SAPIA) database. Agricultural Research Council. Plant Protection Research 

Institute. South Africa. Accessed 2009. Available online: http://www.agis.agric.za/wip/ 

Senge P, Smith B, Kruschwitz N, Laur J & Schley S (2008) The Necessary Revolution. How individuals and 

Organisations are working together to create a sustainable world. Nicholas Brealey Publishing. London. 

pp.406. 

Simberloff D (2009) We can eliminate invasions or live with them. Successful management projects. Biological 

Invasions 11, 149-157. 

Simberloff D (2003) Eradication - preventing invasions at the outset. Weed Science 51, 247-253. 

Stirling A, Leach M, Mehta L, Schoones I, Smith A, Stagl S & Thompson J (2007) Empowering Designs: towards 

more progressive appraisal of sustainability. STEPS Working Paper 3, Brighton, STEPS Centre. 

Strauss A & Corbin J (1998) Basics of Qualitative Research. Techniques and procedures for developing grounded 

theory. (2 nd Edition). SAGE Publications. London. pp. 312. 

Wilson J RU, Richardson DM, Rouget M, Procheş Ş, Amis MA, Henderson L & Thuiller W (2007) Residence time 

and potential range: crucial considerations in modelling plant invasions. Diversity and Distributions 13, 11- 

22. 



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APPENDIX Figure 3. Mind-map of how we see contextual information contributing to risk estimation and response management of Melaleuca invasions in South Africa 

Denotes application of the 

precautionary principle 

Forestry nursery 

records? 

Other Melaleuca 

species found on 

forestry estate 

Species knowledge 

e.g. M. ericifolia 

ecology well studied 

Invasiveness and impacts 

elsewhere 

e.g. M. quinquenervia well 

studied & control 

techniques refined 

Emergence pattern 

Emergence following 

plantation clear fell and in 

forest understory > 

surveillance strategy 

adapted 

On-site observations 

of extent and recruitment 

e.g. M. ericifolia not invasive elsewhere but considered high-risk 

Habitat suitability 

Ease of eradication 

e.g. M. quinquenervia 

Biological data 



Rate of spread 

Actual distribution 

Refined 

estimated 

RISK 

Response planning, 

prioritisation, resource 

allocation and action 

(i.e. risk reduction) 

223

Code of conduct on horticulture and invasive alien plants 

V H Heywood 

Centre for Plant Diversity & Systematics, School of Biological Sciences, University of Reading, 

RG40 6AS, UK. Email: v.h.heywood@reading.ac.uk 

It is estimated that about 80% of invasive alien plants in Europe have been are introduced 

through the horticultural industry and trade for ornamental purposes. This major pathway must 

be addressed to help prevent further entry and spread of invasive alien plants in Europe. 

Currently, only a few legislation instruments are in place and management programmes are 

limited. As an urgent first step, voluntary measures to tackle the problem and raise awareness 

among the horticultural sector and the public are needed. It is in this context that the Council of 

Europe and the European and Mediterranean Plant Organization (EPPO) have cooperated in 

preparing a code of conduct on horticulture and invasive alien plants for European and 

Mediterranean countries,. This code of conduct, published in 2009, provides essential 

background information and a set of guidelines for Governments and the horticultural and 

landscape sectors on regulation concerning invasive alien plants, plant wastes disposal, labelling 

of plants, proposing alternative plants, publicity, etc. The code is voluntary and requires action at 

the country level to promote and implement its recommendations. 



224

Industry view on importance and advantages of a Code of Conduct on horticulture and 

invasive alien plants 

Anil Yilmaz 

Antalya Exporter Unions General Secretariat, Turkey. E-mail: yilmaza@aib.org.tr 

The International Association of Horticultural Producers (AIPH) represents horticultural 

producers' organisations all over the world. The horticultural industry supports the aim to 

preserve the biological diversity. The reinforcement of the biological diversity in urban areas, the 

improvement of the greening in cities is considered and supported as the essential aim of national 

strategies for biological diversity. Therefore AIPH has interest in the prevention of introduction 

and spread of invasive plants. Their interest is that a Code of Conduct is set up by the sector 

itself or in partnership with government and/or NGO‘s. A code may not just be layed upon the 

sector by the authorities. The rules have to be made by and in agreement with the target group. 

They also can agree on the sanctions, within ethical and legal boundaries. 

Introducing a Code of Conduct can only be successful if there is awareness of the problem and 

stakeholders find it their responsibility to take preventive measures. The organisation that edits 

the Code of Conduct has to be representative for the sector. The form and the content have to be 

accessible, consistent, applicable, realistic and feasible. 

To be effective a Code needs incentives, compliance and assurance. Major reasons to encourage 

self-regulations are 1) preventing government regulation, 2) concern for the image of the sector, 

3) concern for the environment and 4) corporate social responsibility. Although Code of 

Conducts is not a new way of self-regulation, in the horticultural sector it is relatively new. Since 

the middle of the 90-ties codes of conduct or code of practice have been introduced in the field of 

environment and social aspects. Some Codes of Conduct or Code of Practice for preventing the 

spread of invasive plants have been introduced in the last few years. Other initiatives like Action 

Plans or Management Plans towards invasive species, edit by governments, are more 

compulsory. 



225

Effectiveness of policies and strategies in tackling the impacts of Invasive Alien Species on 

biodiverse Mediterranean ecosystems in South-West Australia 

Judy Fisher 

School of Plant Biology University of Western Australia / Fisher Research, PO Box 169, Floreat, 

Perth, Western Australia 6014, Australia. E-mail: ecologist@waanthropologist.com 

When policies, strategies and prioritization processes for invasive alien species (IAS) are based 

on individual species, whether it is at a global, regional or whole of country level, discrepancies 

can occur resulting in long term negative impacts on highly biodiverse ecosystems. The 

Convention on Biological Diversity (Bonn, 2008) invited Parties to consider the impacts of IAS 

on biodiversity, utilizing an ecosystem approach for specific biogeographical regions, and to 

focus on the restoration and rehabilitation of ecosystems degraded by the presence of IAS. 

Research organizations were called on to study the impact of IAS on socio-economic factors, 

health and the environment. Plant invasions in Mediterranean Regions of the world provide the 

opportunity to consider ecosystem impacts of invasive species with ecosystems the focus, rather 

than the invading species. Examples will be provided within woodland, coastal and wetland 

ecosystems in the South-West Australian mediterranean biodiversity hot spot, where financial 

assistance based on individual invasive species, of ―national significance‖, has led to limited 

resources being directed to highly biodiverse ecosystems and consequent ecosystem decline. The 

Copenhagen Meeting on Climate Change (December 2009) identified the vulnerability of 

ecosystems to a changing climate and the importance of maintaining and increasing their 

resilience through good management, thus enhancing their climate mitigation potential via the 

sequestration and storage of carbon in healthy forests, wetlands and coastal ecosystems. In the 

examples provided the decline in the functioning of invaded biodiverse ecosystems will be 

demonstrated. Questions will be raised as to whether investment in invasive species research and 

management would be more effective for biodiversity protection if the strategies and policies 

directing investment were focused on the ecosystem approach rather than a single species 

approach. A diagrammatic representation, based on evidence based ecosystem research, will be 

presented outlining the limited potential to restore transformed invaded ecosystems without early 

intervention. 



226

Combining methodologies to increase public awareness about invasive alien plants in 

Portugal 

Elizabete Marchante 1 , Hélia Marchante 2 , Maria Morais 1 & Helena Freitas 1 

1 CFE-Centre for Functional Ecology. Department of Life Sciences. University of Coimbra. PO 

Box 3046. 3001-401 Coimbra. Portugal; elizabete.marchante@gmail.com, 

maria.morais@ci.uc.pt, hfreitas@ci.uc.pt; 2 CERNAS-Centre for Studies of Natural Resources, 

Environment and Society, Department of Environment. Escola Superior Agrária de Coimbra, 

3040-316 Coimbra, Portugal. hmarchante@gmail.com 

Introduction 

Citizens represent a vector of introduction and spread of invasive alien species 

(IAS) and, on the other hand, can play a major role in helping to prevent and 

control IAS. Even though IAS and their consequences are recognised by the 

Portuguese law since 1999, a large proportion of the population is still unaware 

of biological invasions. To reduce this gap, the research team has devoted a 

considerable effort to promote public awareness and engage the public with 

IAS, namely invasive plants. A web page was developed, field-work projects 

for university students and training courses for professionals dealing with 

exotic plants and for schoolteachers were organized. Online questionnaires 

were performed targeting municipalities, forestry associations, horticultural 

trade, etc. Additionally, printed documents about invasive plants in Portugal, 

including a field guide, a technical document about identification and control, 

bookmarks and postcards were produced. Finally, workshops and other 

initiatives were organized. At the same time, an effort is being made to 

evaluate the effectiveness of these various approaches. Overall, public 

awareness about IAS is increasing, but more work is needed. Future work will 

involve diversifying the field actions, namely by establishing protocols with 

local and regional administrative entities, and planning a pilot early-detection 

programme. 

Biological invasions represent one of the main threats to biodiversity worldwide, they alter 

ecosystem services and have significant economic impacts (Mooney & Hobbs 2000, Lambdon et 

al. 2008, Gaertner et al. 2009, Hulme et al. 2009, Vilà et al. 2009). In Europe alone, the known 

economic impacts are estimated at about €10 billion/year (Hulme et al. 2009). Scientists, 

politicians (Commission of the European Communities 2008, Ministério do Ambiente 1999) and 

Global Organizations (ISSG, UICN, Millennium Assessment), all recognize the magnitude of the 

problems caused by invasive alien species (IAS), stressing the need for strategies that reduce 

their impacts on biodiversity. Although establishment of invasive species can be prevented if 

they are controlled soon after introduction, management and control of IAS already established 

and spread is a complex and generally difficult and costly task. Therefore, the more cost-efficient 

strategy is to prevent the introduction of IAS. To achieve this, a strong investment in prevention 

and public awareness about IAS is essential. The general public is an important vector of 

introduction and spread of IAS (Ruiz & Carlton, 2003), but, if strongly engaged, a public well 



227

informed can help to prevent further introductions of IAS and have a major role in helping to 

control or mitigate them. Furthermore, in order to develop sustainable management programs for 

IAS, scientists and other professionals dealing with exotic species, as well as decision-makers, 

need to be adequately informed about IAS. Importantly, public awareness activities need to be 

carefully evaluated in order to allocate available resources to the approaches that are the most 

successful at changing attitudes and actively engage the target publics. 

In Portugal, although IAS and their consequences are recognized by the Portuguese law since 

1999 (Decreto-Lei nº 565/99), many people are not aware of biological invasions and of the 

problems they cause. Even though the main focus of the research team is on scientific research, 

soon after initiating work on invasive plants we realized both the huge lack of awareness of the 

Portuguese population about this theme and the importance of communicating it countrywide. 

Therefore, we have made a strong commitment to engage the public with IAS, specifically by 

including public awareness tasks and activities in our research projects as much as possible. 

Since 2003, several initiatives and methodologies have been used to raise awareness about 

invasive plants in Portugal (Table 1): 1) development of a web-page, 2) summer field-work 

projects, 3) training courses, 4) online questionnaires aiming to survey the awareness of different 

target publics, 5) printed documents about invasive plants in Portugal and 6) other activities, 

namely thematic workshops, participation in forums, school talks, public events, etc. These 

initiatives and methodologies have reached about 0.2% of the Portuguese population (excluding 

the outreach of the web-page which is available to a larger population), including very diverse 

target publics. Funding for the activities came mainly from research and science communication 

projects, being designed specifically only for some of the activities, namely for field-work 

projects and printed documents, while for others the estimates are mostly based on man-working 

days (Table 1). 

Development of a Web page 

Aims: to produce simple available information about invasive plant species in Portugal and 

biological invasions in general; to communicate results of scientific projects and multiple public 

awareness activities. 

Description: a web page was developed and is available at http://www.uc.pt/invasoras; this 

was the first web page in Portugal with information about invasive alien plants at the country 

level. All information is available in Portuguese, since the main target public is the Portuguese 

population, but several menus are available also in English. The menus in the web page include: 

1) biological invasions (with basic information about the process of plant invasion, 

characteristics, impacts and management of invasive plants, etc.); 2) invasive plants in Portugal 

(including detailed information about the plant species listed as invasive in the Portuguese 

legislation and some other species not yet listed but with invasive behaviour; and including also 

a list of potentially invasive plants – information about these species will be further developed in 

the near future); 3) research and other projects (namely objectives, tasks and main results of 

some of the on-going research projects about invasive species); 4) on-going activities of public 

awareness; 5) publications and outputs and 6) news. Additionally, an e-mail address is available 

for users to consult experts about invasive plants. 



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2 nd Table 1 - Initiatives and methodologies used to raise public awareness about invasive plants 

in Portugal by a team from CFE and CERNAS. 

Type 

activity/methodology 

of 

Target public 

Public 

reached* 

Time frame 

Costs 

(€) *** 

Web-page 

http://www.uc.pt/invasoras 

General public > 130 200 Available since 2003 5 500 

Field-work projects University students > 170 9 annual editions 180 

and professional, 

since 2003 (1 week 000 

mainly of 

each) 

environmental, 

forestry and 

biological sciences 

Training courses: 

Identification and control Technical publics 40 

3 editions: 2005, 3 500 

of IAP** 

dealing with IAP** 

2006 & 2007 (25h 

Biological invasions and Schoolteachers 25 

each) 

1 200 

environmental education 

1 edition: 2009 

Online questionnaires Municipalities 81 

(25h) 

Distributed during 2 500 

Forestry associations 51 

2006 and 2007 

Higher education 52 

courses 

33 

Horticultural industry 4 

Botanical gardens 

Printed documents: 

Plant species technical Technical publics > 2 Available since 2005 6 400 

profiles 

dealing with IAP** ...................... (out of print) .... 

Invasive plants field guide General public > 2 000 Available since 2009 18 000 

Postcards to color 

8 to 12 years old > 2 000 (out of print) 

Bookmarks collection 

Other initiatives: 

general public > 10 000 Available since 2009 

Available since 2009 

Thematic workshops Mainly students, but > 650 10, since 2008 5 000 

Science and nature forums also the general > 1 500 4, since 2008 

and fairs 

public 

> 1 500 > 30, since 2007 

Talks 

General public and 

students 

General 

students, 

public, 

horticultural trade, 

conservation experts, 

foresters, etc. 

sub-total (not > 20 000 

considering the web (~0.2% 

page): 

Portuguese 

60 100 

total: 

population) 

> 150 000 

* Approximate numbers; **IAP – invasive alien plants; *** some values are rough estimates 

based on man-days to develop the activities, though such values were not, in most of the cases, 

specially allocated to fund these tasks. 

229 


Results and evaluation: the web page is available from April 2003 and since then more than 

130 200 visitors accessed it, corresponding to more than 605 000 ―clicks‖. Although a large 

percentage of visitors are from Portugal and Portuguese speaking countries, users from over 80 

countries have visited the page. Numerous people and institutions use the page e-mail address to 

request technical assistance on control methodologies and species identification, as well as to ask 

for collaboration in public awareness activities and environmental education sessions. These 

contacts enable this web page to be validated as an effective awareness tool. 

Field-work Projects 

Aims: to increase awareness amongst university students and young professionals, mostly 

from areas related to environmental, forestry and biological sciences, namely through training 

and collaboration on control of invasive plants in Conservation Areas. 

Description: the projects include different approaches to engage the target public: 1) 

participation in control of invasive plant species, namely Acacia longifolia, A. dealbata, 

Cortaderia selloana and Carpobrotus edulis, 2) short courses about IAS and Nature 

Conservation, and 3) small projects involving invasive plants, namely scientific experiments and 

public awareness activities for the general public and schools (Figure 1). The philosophy behind 

these projects is to strongly engage the target public with this theme, through learning about IAS, 

hands-on activities to control invasive plants and creation of a healthy and fun working/learning 

environment. In 2003, when the first project was organized, this type of project was quite 

innovative in Portugal and the public was very receptive and enthusiastic. Although activities 

were planned for 20 volunteers in each field-work project, the number of inscriptions has been 

always much higher, reaching more than 80 in some cases. These projects were developed 

mostly in summer vacations, occasionally at Easter Time, for one week, with volunteer groups 

sharing accommodation, meals, learning, working and leisure time. 

a b c 

Figure 1 - Field-work projects. a. control of Carpobrotus edulis at Reserva Natural das Dunas 

de São Jacinto (2004), b. development of scientific experiments, c. short-courses about 

invasive plants. 

Results and evaluation: nine field-work projects were organized in four Conservation Areas 

in Portugal involving more than 170 volunteers, who contributed to the control of four invasive 

plant species. These projects were very effective and successful in training people and increasing 



230

awareness, especially among university students and young professionals. Due to the continuity 

of the projects, usually one each year since 2003, the target public has grown accustomed to 

them and frequently unknown people request information about the future events. This type of 

activity showed to be engaging and effective: after participating, several volunteers became 

involved in invasive species projects, and some of them now work professionally in this subject. 

Furthermore, it has been a good way to encourage the Conservation Areas staff and to publicize 

their work on the management and control of invasive plants. A questionnaire is currently being 

prepared targeting all the previous participants in order to better quantify the effectiveness of this 

approach. 

Training courses 

Aims: to provide tools to capacitate the trainees to 1) identify and manage invasive plants 

present in Portugal (technical courses for professionals dealing with exotic and invasive plants) 

and 2) develop educational projects and activities about invasive species (courses for school 

teachers). 

Description: the courses involved theoretical sessions, laboratory and field practical sessions 

and field trips to areas invaded by different species. Three courses (ca. 25h each) about 

identification and control of invasive plants were organized in 2005, 2006 and 2007. The target 

public was technicians from municipalities and nursery industry, conservation and forestry 

experts, researchers, and other technical staff who deal with exotic and invasive species. In 2009, 

a different course was offered to school teachers, as they are in a privileged position to 

disseminate information about this theme among young people. The program was adapted from 

the technical course, focusing more on the theory behind biological invasions and considering 

environmental education projects and activities that could be developed and used in school 

classes. 

Results and evaluation: ca. 40 technicians and 25 teachers attended the courses. This 

approach has proved to be very effective in changing attitudes. Some technicians have actively 

integrated the knowledge gained in the course in their regular activities, namely in invasive 

control programs or excluding invasive species from their lists of ―working species‖. Some of 

the teachers developed programs to be applied during the forthcoming school year in their 

schools and as a consequence many students have heard about this theme and many have been 

involved in hands-on activities. 

Online questionnaire 

Aims: to survey the knowledge/awareness of different target publics who deal with exotic and 

invasive plants about their use and related legislation. At the same time, the questionnaire aimed 

to raise public awareness about IAS and Portuguese legislation about non-indigenous species, 

start the mapping (presence vs. absence only) of invasive plants in continental Portugal and 

survey the control actions being developed in the country. 

Description: a questionnaire was undertaken targeting technical publics who deal with exotic 

and invasive plant species, namely municipalities, forestry associations, horticultural trade and 

industries, botanical gardens and higher education institutions/courses in which forestry, 



231

environmental and biological sciences are part of the curricula. Most questionnaires were carried 

out online and sent to a list of institutions previously selected. While municipalities, botanical 

gardens and institutions of higher education were all surveyed, although not all responded, 

forestry associations and horticultural trade and industry were more difficult to trace and 

consequently the ―total‖ public was sub-sampled. Concerning horticultural trade and industry, in 

person questionnaires were also performed at a horticultural fair. Questionnaires were performed 

during 2006 and 2007 and they were adapted to each target public, with some questions shared 

and other distinct from each other. Full text versions of the questionnaire and results may be seen 

at http://www.uc.pt/invasoras (in Portuguese). 

Results and evaluation: 221 institutions returned the questionnaire; from these, 81 were 

municipalities, 51 forestry associations, 52 higher education departments/courses, 33 

horticultural trade and industries and 4 botanical gardens. Municipalities and horticultural 

trade and industry were the target publics with the lowest percentages of response to the 

questionnaire (Figure 2a). Although Portuguese legislation about non-indigenous species is 

from 1999, ca. 8 years after, the results showed that unawareness about IAS, amongst these 

target publics still exists, with ca. 33% of the horticultural traders and industries and forestry 

associations being unaware of the legislation (Figure 2 

Figure 2b). Establishment/courses of higher education were asked if biological 

invasions/invasive species were part of the curricula and if legislation was referred to during the 

classes: from the 52 respondents, 44 said biological invasions were a subject in classes, but only 

24 referred to the present legislation. 

Respondents (%) 

Awareness about legislation (%) a b 

100 

80 

60 

40 

20 

0 

100 

80 

60 

40 

20 

0 

Municipalities Forestry 

associations 

Municipalities Forestry 

associations 

Botanical 

gardens 

Botanical 

gardens 

Horticultural 

trade 

Horticultural 

trade 

Higher 

education 

institutions 



232

Figure 2 – a. Percentage of inquired from each target public that responded to the 

questionnaire about invasive plants and related legislation. b. Awareness about Portuguese 

legislation concerning non-indigenous species. 

Senecio bicolor 

Oxalis pes-caprea 

Hakea salicifolia 

Galinsoga parviflora 

Acacia karroo 

Eryngium pandanifolium 

Eichhornia crassipes 

Datura stramonium 

Acacia retinodes 

Acacia pycnantha 

Pittosporum undulatum 

Erigeron karvinskianus 

Acacia mearnsii 

Robinia pseudoacacia 

Carpobrotus edulis 

Ailanthus altissima 

Acacia saligna 

Acacia longifolia 

Hakea sericea 

Acacia melanoxylon 

Acacia dealbata 

0 20 40 60 80 100 

a 

Species perceived as problematic by the 

different entities (%) 

b 

Trandescantia fluminensis 

Spartina densiflora 

Senecio bicolor 


Pittosporum undulatum 

Oxalis pes-caprea 

Myriophyllum brasiliensis 

Ipomoea acuminata 

Hakea sericiea 

Hakea salicifolia 

Galinsoga parviflora 

Eryngium pandanifolium 

Erigeron karvinskianus 

Elodea canadensis 

Eichhornia crassipes 

Datura stramonium 

Conyza bonariensis 

Carpobrotus edulis 

Azolla filiculoides 

Arctotheca calendula 


Acacia retinodes 

Acacia pycnantha 

Acacia melanoxylon 

Acacia mearnsii 

Acacia longifolia 

Acacia karroo 

Acacia dealbata 

Acacia cyanophylla 

0% 20% 40% 60% 80% 100% 

intentional acidental unknown 

Figure 3 - a. Invasive species perceived as problematic by municipalities and forestry 

associations responding the questionnaire. b. Mode of introduction of invasive plant species, 

according to answers from municipalities and forest associations. 

The questions from municipalities and forestry associations‘ questionnaires were, in general, 

the same. However, results showed that both publics have quite different knowledge and 

perception about invasive plants, which is probably related to their distinct professional aims and 

obligations. Ninety percent (90%) and 65% of the forestry associations and municipalities, 

respectively, declared to have invasive species present in their territories. Perception that these 

species cause problems was different, with 74% of the forestry associations recognizing that 

invasive species promote negative impacts while only 40% of the municipalities had that view. 

However, only 6% of the forestry associations develop management action in order to control 

invasive plants, claiming that such actions were out of their duties, while 57% of the 

municipalities responded that they make an effort to control invasive plants. The problems 

associated to invasive plants were also distinct for both target publics: while municipalities 

elected reduction of biodiversity (67%) and economic problems (57%) as the main impacts 

associated with these species, forestry associations recognized economic (85%) and productivity 

(59%) problems, and only 50% considered invasive plants to be a threat to biodiversity. When 



233

asked directly about which invasive species cause more problems, the answers revealed that the 

most widespread species are not always perceived as the ones causing more negative impacts: 

Acacia dealbata, A. melanoxylon, Hakea sericea, A. longifolia, A. saligna, Ailanthus altissima, 

Carpobrotus edulis and Robinia pseudoacacia were the species most often quoted as problematic 

by municipalities and forestry associations; some invasive plant species were not perceived as 

causing problems by these publics (Figure 3a). 

The perceived mode of introduction of the different invasive species was also surveyed. 

Although results differed from species to species (Figure 3), for most species (70%) the reason 

for introduction was unknown to the respondents, while for 23% and 7% intentional and 

accidental introductions were evoked, respectively. 

Figure 4 - Distribution maps of selected invasive plant species in Portugal according to 

responses to questionnaires sent to municipalities and forestry associations. b black k one or 

more municipality or forestry association responded to the questionnaire and signalled the 

species as present in the area; g grey y municipality or forestry association responded to the 

questionnaire, but none signalled the species as present in the area; white, area where no 

municipality or forestry association responded to the questionnaire. 



234

Answers from municipalities and forestry associations allowed the mapping of the major 

invasive plants along the continental Portuguese territory to be initiated, considering 

presence/absence per area of municipality (see Figure 4). Results show that some invasive 

species are already present in many Portuguese municipalities. However, the lack of answers 

from non-respondent municipalities or forestry associations has obvious implications in the 

maps, with data missing for many regions. Considering this limitation and although these results 

do not allow the mapping of abundance of each species, results suggest that Acacia dealbata is 

the most widespread invasive species, which is in agreement with our own perception 

(Marchante et al. 2008). On the other hand, for example Eichhornia crassipes was signalled by 

few municipalities or forestry associations, but it is present in more regions of the country 

(Marchante et al. 2008). 

When analyzing the results of the questionnaires, it is important to keep in mind that they 

reflect the knowledge and sensitivity/awareness of the respondents, which may sometimes not 

reflect rigorously the actual situation, since species that are more problematic and frequent are 

more easily spotted and remembered. In addition, only a proportion of the target population 

answered the questionnaire. Other point that must also be taken into account when interpreting 

the results is that species may have been sometimes mistaken by some other species. 

These questionnaires were an important source of information about the awareness of 

legislation, invasive plant species distribution, perception of species which are problematic, their 

perceived mode of introduction, etc. In addition, such survey increased public awareness, and 

nowadays many technicians from these target publics contact our team asking for information or 

consultation about management of invasive plants. 

Printed documents about invasive plants in Portugal 

Aims: to produce printed documents that can be used to raise awareness about invasive plants. 

Description: the different activities organized and the contact with the public highlighted the 

need of printed documentation about invasive plants. To fill this gap, different documents were 

produced, targeting different publics (Figure 5). 

Plant species technical profiles (2005): technical document about identification and control of 

the most common and problematic species in Portugal (Marchante et al. 2005). This document 

includes the profiles of the 30 plant species considered invasive by the Portuguese legislation, 

plus three other species that are also invasive although not yet listed in the legislation. This 

publication targets technical publics dealing with invasive plants, and was made available both 

online (in two platforms – www.uc.pt/invasoras and www.pluridoc.com) and in a printed 

version. The printed version was distributed to professionals working with exotic plants and 

public and private institutions responsible for the management of areas invaded by alien plants. 

Invasive plants field guide (2008): publication of the first field guide of invasive alien plants 

in continental Portugal (Marchante et al. 2008). More than 80 plants species were included, 

considering invasive plants and other potentially invasive plants (casuals and naturalized), which 

are either invasive in other regions of the world with similar climate, show sporadic invasive 

behaviour in Portugal or belong to genera which include invasive plants in the country. The 

guide includes as well an introduction to biological invasions and invasive plant species. 



235

Booklet with postcards to color (2008): although this theme can be somewhat complex to 

young children, it is important to raise awareness from an early age. A small booklet, with a 

collection of postcards, of 13 of the worst invasive plant species in Portugal was developed 

targeting school children. The booklet includes a fixed part (to keep, with simple information) 

and postcards to detach. Each postcard is the drawing of an invasive plant; the reverse is an 

ordinary postcard to write a message – the idea is that each child can learn a bit about invasive 

plants, personalize the card, colouring it, and write a message to friends and family about this 

theme, working themselves as ―vectors of dissemination of information‖. Postcards were initially 

made for children from 8 to 12 years old, but worked also fine with younger and older students. 

Bookmarks collection (2008): 13 bookmarks were made about the worst invasive plants in 

Portugal. Each bookmark has simple information about invasive plants in general, information 

about a specific invasive plant and the link of the website where more information and contacts 

can be looked after. These are targeted to the general public, and used for different publics and 

activities. The idea was to have available a simple, appealing (and cheap) publication that can be 

given to everyone. 

a b 

c d 

Figure 5 Examples of printed documents about invasive alien plants in Portugal. a. ―Plantas 

Invasoras em Portugal – guia para identificação e controlo‖ [technical profiles about 

identification and control of invasive plants in Portugal], b.‖Guia prático para a identificação 

de Plantas Invasoras de Portugal Continental‖ [field guide about invasive plants in continental 

Portugal], c. Postcard from the ―Booklet with postcards to color‖, d. Bookmark about 

Eichhornia crassipes. 

Results and evaluation: the technical profiles about invasive plants are available in a platform 

where they are the third most downloaded document amongst several thousand, with more than 

2000 downloads since July 2007; the printed version (500 copies) is out of print. Frequent 

requests for the printed version and consultation concerning control of different invasive plant 

species are received. Two thousand free copies of the field guide were printed and are now out of 

print; the reviews/criticisms to this first edition were very good and a new edition is being 

planned. This edition was distributed, mainly under direct request, to several official entities and 

people interested in the theme, reaching very distinct publics; it was also distributed to some 

public and school libraries, being available to people all over the country. The bookmarks were 

mostly distributed to entities dedicated to science communication and environmental education, 



236

ut also to conservation areas, schools and the general public in nature and science festivals and 

other events. Distribution is still ongoing, and the distribution together with a national newspaper 

is being prepared. Postcards were mainly used for school children and activities organized for 

this specific public. As much as possible, the printed documents were used together with 

different initiatives organized in order for them to be understood in context. 

Other initiatives 

Aims: to raise awareness about invasive plants and to communicate results of research 

projects to different publics. 

Description: thematic workshops were organized, mainly targeting school students, but also 

the general public. These workshops included different activities (Figure 6), such as short talks, 

hands-on activities for the control of invasive plants, interactive games and invasive plant 

identification games (Reis et al. submitted). Further dissemination of information about invasive 

plants was attained through participation in several environmental conferences, forums, 

conference and school talks, etc, targeting very diverse publics (the general public, school 

children and students, university students, foresters, horticultural trade, conservation experts, 

etc). 

Results and evaluation: since 2005, more than 30 talks were given, 10 workshops and handson 

activities were carried out, and science and nature forums and fairs for different publics were 

joined. The contexts and publics of these initiatives were very diverse. As a result, over the past 

few years and all over the country many citizens became aware about invasive plants. 

Effectiveness of the workshops organized for schools was accessed through questionnaires sent 

to schools, one year later, targeting students who attended the workshop as well as a control 

group who did not attend it. Results showed that, after one year, the participants in the workshop 

knew significantly more about invasive species and recognized more invasive plant species than 

non-participant students (Reis et al. submitted). 

a b c 

d 

e 

f 

Figure 5 - Thematic workshop about invasive plants. a-b. short-talks, c-d. recognition games, 

e-f. interactive games. 



237

Final considerations and future work 

After several years communicating about invasive alien plants in Portugal, our perception is 

that awareness about biological invasions has increased, although lack of awareness is still a 

substantial reality. There is still a lot to be done! Nevertheless, information on invasive alien 

species is nowadays more frequent in the media and many people and institutions have 

contributed, and are committed to continue, to raise public awareness. The diversified 

methodologies and strategies used by the team from CFE and CERNAS are slowly contributing 

to change mentalities and attitudes, making the public better educated on the topics of invasive 

plants and biological invasions. This public can then have an important role in the prevention, 

early-detection and the control of invasive species. 

After using different approaches, our perception is that methodologies which include handson 

or interactive activities and involve the participants for a longer time are more engaging and 

efficient in increasing awareness about invasive plant species (Reis et al. submitted). The 

estimated number of people reached by the different activities/approaches is higher than 150 000 

(Table 1). However, the main contribution to this number is the web page, which effectively 

contributes to raise awareness and provide information, but which is probably less effective to 

make people change their attitudes about exotic and invasive plant species than more interactive 

activities. A stronger effort and investment needs to be made in order to better evaluate the 

activities/approaches used to communicate on IAS. Evaluation of effectiveness is not always 

easy. Nevertheless, funding for communication is often scarce and so it is important that it can be 

used in the most efficient way, targeting approaches that are more effective in changing attitudes 

and engaging the public with this subject. The collaboration of experts on communication is also 

of utmost importance if a well-coordinated and effective campaign is to be promoted. 

We are committed to this challenge of engaging the public with IAS and will continue to do 

so along with our research activities. For that, we are planning to diversify activities in the field, 

establishing protocols with local and regional administrative agencies, implementing new tools 

and interactive maps on the web page, extending the questionnaires to conservation experts, 

forestry authorities, and general public, preparing updated versions of the printed materials and 

initiating a pilot early-detection programme. 


Special thanks to volunteers of field-work projects, to Catarina Reis and to all who helped and 

participated in the different activities. FCT-MCES & FEDER (POCI2010) are acknowledged for 

funding the projects INVADER (POCTI/BSE/42335/2001), INVADER II (POCI/AMB/ 

61387/2004) and CV-127-107. 

References 

Commission of the European Communities (2008) Towards an EU strategy on invasive species - Communication 

from the Commission to the Council, the European Parliament, the European Economic and Social 

Committee and the Committee of the Regions. 

http://ec.europa.eu/environment/nature/invasivealien/index_en.htm [accessed on January 2009] 



238

Gaertner M, Den Breeyen A, Cang H & Richardson DM (2009) Impacts of alien plant invasions on species richness 

in Mediterranean-type ecosystems: a meta-analysis. Progress in Physical Geography 33(3), 319-338. 

Hulme PE, Pyšek P, Nentwig W & Vilà M (2009) Will Threat of Biological Invasions Unite the European Union? 

Science 324 (5923), 40-41. 

Lambdon PW, Pyšek P, Basnou C, Hejda M, Arianoutsou M, Essl F, Jarošìk V, Pergl J, Winter M, Anastasiu P, 

Andriopoulos P, Bazos I, Brundu G, Celesti-Grapow L, Chassot P, Delipetrou P, Josefsson M, Kark S, Klotz 

S, Kokkoris Y, Kühn I, Marchante H, Perglová I, Pino J, Vilà M, Zikos A, Roy D & Hulme PE (2008) Alien 

flora of Europe: species diversity, temporal trends, geographical patterns and research needs. Preslia 80, 

101–149. 

Marchante H, Marchante E & Freitas H (2005) Plantas Invasoras em Portugal – guia para identificação e controlo. 

Ed. dos autores. Coimbra. (in Portuguese) 

Marchante E, Freitas H & Marchante H (2008) Guia prático para a identificação de Plantas Invasoras de Portugal 

Continental. Coimbra Imprensa da Universidade de Coimbra. 183 pp. (in Portuguese) 

Ministério do Ambiente (1999) Decreto-lei n.º 565/99 de 21 de Dezembro. In: Diário da República - I Série - A. 

295: 9100-9114. (in Portuguese) 

Mooney HA & Hobbs RJ (2000) Invasive Species in a Changing World. Island Press, Washington DC. 

Reis CS, Marchante H, Freitas H & Marchante E. Public perception of invasive plant species: assessing the impact 

of workshop activities to promote young students awareness. Submitted to Public Understanding of Science. 

Ruiz G M & Carlton JT (2003) Invasive Species: Vectors and Management Strategies (p. 484). Island Press. 

Vilà M, Basnou C, Pyšek P, Josefsson M, Genovesi P, Gollasch S, Nentwig W, Olenin S, Roques A, Roy D, Hulme 

PE & DAISIE partners (2009) How well do we understand the impacts of alien species on ecosystem 

services? A pan-European, cross-taxa assessment. Frontiers in Ecology and Environment 8(3), 135-144. 



239

Expérience tunisienne des Champs Ecoles Paysans sur la lutte intégrée contre une plante 

exotique envahissante : Solanum elaeagnifolium 

M. Mekki 1 , M. M‘hafdhi 2 , R. Belhaj 2 and K. Alrouechdi 3 

1 

Institut Supérieur Agronomique de Chott Meriem, BP 47, 4042 Chott Meriem (Tunisie) ; email 

: mekki.mounir@iresa.agrinet.tn 

2 

Direction Générale de la Protection et du Contrôle de la Qualité des Produits Agricoles, 30 Rue 

Alain Savary, 1002 Tunis (Tunisie) ; e-mail : ridha.belhaj@iresa.agrinet.tn 

3 

FAO, Plant Production & Protection Division (AGP), Viale delle Terme di Caracalla 

00153 Rome, (Italy) ; e-mail : Khaled.Alrouechdi@fao.org 

Introduction 

La morelle jaune (Solanum elaeagnifolium Cav. # SOLEL) est originaire du 

continent américain. Actuellement, elle est considérée une plante exotique 

envahissante (PEE) dans les cinq continents. En 2008, la FAO a lancé un 

programme de coopération technique (TCP/RAB/3102) entre le Maroc et la 

Tunisie pour la gestion des plantes envahissantes et en particulier SOLEL. Les 

activités de ce programme ont duré 18 mois (juillet 2008-décembre 2009) et 

l‘un de ses objectifs était l‘installation de trois Ecoles Champs Paysans (CEP) 

sur la lutte intégrée contre SOLEL. Ces CEP ont concerné trois régions du pays 

(Kairouan, Sidi Bouzid et Mahdia) et ils ont impliqué environ 75 agriculteurs et 

techniciens. Les participants se sont rencontrés au moins sept fois, à raison 

d‘au moins 3 heures par rencontre. Le programme des rencontres prévoyait des 

échanges et des activités aux champs relatifs à la caractérisation de SOLEL 

(identification et bio-écologie) et les moyens de lutte contre cette espèce 

(sarclages manuel et mécanique, désherbage chimique, co-compostage, 

cultures étouffantes, etc.). Ces CEP étaient une bonne occasion d‘analyser avec 

les agriculteurs et les techniciens agricoles les pratiques actuelles de lutte 

contre SOLEL et de leur proposer des pratiques alternatives pour mieux gérer 

cette espèce. 

En Tunisie, plusieurs plantes exotiques sont introduites dans le pays de façons intentionnelle 

ou accidentelle. L‘absence d‘un système de gestion des Plantes Exotiques Envahissantes (PEE) 

et l‘insuffisance des moyens matériels et humains pour surveiller le territoire afin d‘empêcher 

l‘introduction et l‘établissement de ces espèces a permis à la morelle jaune (Solanum 

elaeagnifolium Cav. # SOLEL) d‘entrer dans le pays, de s‘y établir silencieusement durant 

quelques décennies et de devenir envahissante depuis quelques années (Mekki, 2007). SOLEL 

est une mauvaise herbe très redoutable dans son aire d‘origine (Boyd et al., 1984). Les parcelles 

fortement infestées sont souvent abandonnées et leur valeur foncière et locative est très réduite. 

De plus, cette plante est reconnue comme toxique pour les animaux et elle menace la biodiversité 

des milieux infestés. Elle est très fréquente dans les milieux perturbés (bordures de routes, 

aménagements paysagers, pâturages, cultures, etc.). Dans la région méditerranéenne, elle figure 

sur la liste A2 des PEE de l‘Organisation Européenne de Protection des Plantes (OEPP) et est 

recommandée pour réglementation. En Tunisie, elle a été signalée pour la première fois en 1985 



240

à l‘office des terres domaniales d‘El Alem - délégation de Sbikha. On présume qu‘elle n‘était pas 

présente dans le Pays avant 1960 (Mekki, 2006). Actuellement, elle est rapportée dans 16 

gouvernorats du pays (Tableau 1). 

Tableau 1 - Distribution géographique de la morelle jaune en Tunisie (DGPCQPA 1 , 2009) 

Gouvernorat Superficie infestée (ha) Biotopes infestées 2 

Kairouan 20 000 TC, TNC 

Sidi Bouzid 15 000 TC, TNC 

Sousse > 100 TC, TNC 

Sfax > 70 TC, TNC 

Ariana > 30 TC, TNC 

Manouba < 10 TC, TNC 

Mahdia < 10 TC, TNC 

Zaghouan < 10 TC, TNC 

Monastir < 10 TC, TNC 

Ben Arous < 10 TC, TNC 

Nabeul < 1 TNC 

Gabes < 1 TNC 

Gafsa < 1 TNC 

Mednine < 1 TNC 

Beja < 1 TNC 

Le Kef < 1 TNC 

1 : DGPCQPA : Direction Générale de la Protection et du Contrôle de la Qualité des Produits 

Agricoles 

2: TC : terres cultivées ; TNC : terres non cultivées 

Depuis 2005, la Tunisie a accru son intérêt pour la gestion des PEE et plus particulièrement 

pour SOLEL. Le pays a donc sollicité le soutien du bureau sous régional de l‘Organisation des 

Nations Unies pour l‘Agriculture et l‘Alimentation (FAO-SNE) pour mener un programme de 

coopération technique régional sur la gestion des PEE et en particulier SOLEL. Ce programme 

(TCP/RAB/3102) a démarré en juillet 2008 et a été clôturé en décembre 2009. Il avait pour 

objectifs de : 

1. Sensibiliser les agriculteurs, les autorités et les Organisations Non Gouvernementales 

(ONG) concernées par la protection des plantes et de l‘environnement aux risques que 

SOLEL représente. 

2. Renforcer les compétences des techniciens et des agriculteurs en matière de lutte intégrée 

contre SOLEL. 

3. Elaborer une stratégie nationale de gestion de SOLEL et des PEE. 

4. Etablir un réseau national pour appliquer la stratégie nationale de gestion de SOLEL et 

des PEE. 

5. Préciser la distribution de SOLEL dans le pays. 

6. Analyser les Risques Phytosanitaires (ARP) de SOLEL. 

7. Dresser une liste des plantes exotiques potentiellement envahissantes pour le pays. 

8. Préparer un projet régional relatif à la gestion des PEE, qui implique le maximum de pays 

méditerranéens. 



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Les Champs Ecoles Paysans (CEP) ont été développés en Indonésie pour limiter les impacts 

négatifs des pesticides agricoles et développer la lutte intégrée contre les ennemis des cultures. 

La base des CEP est l‘apprentissage par la découverte, la pratique et l‘expérimentation (Braun et 

al. 2006). Ces espaces d‘apprentissage et d‘échange fournissent aux participants l‘opportunité de 

découvrir des pratiques alternatives afin d‘améliorer leurs conditions. La première expérience 

des CEP a été réalisée en 1989 et a impliqué 200 agriculteurs dans un programme de lutte 

intégrée contre les ennemis des rizières. Depuis, cette expérience s‘est répandue dans plusieurs 

pays du monde. Dans le cadre du TCP/RAB/3102 nous avons installé 3 CEP sur la lutte intégrée 

contre SOLEL afin d‘amener les participants à adopter volontairement cette approche de lutte. 

Matériel et Méthodes 

Lors de l‘atelier national sur la gestion intégrée des plantes envahissantes, en particulier 

SOLEL, tenu à Sousse du 19 au 21 janvier 2009, les participants ont défini les lieux 

d‘installation des CEP sur la lutte intégrée contre SOLEL (Figure 1) : 

La délégation la plus infestée du gouvernorat de Kairouan (Sbikha), 

La délégation la plus infestée du gouvernorat de Sidi-Bouzid (Jelma) et 

Le gouvernorat de Mahdia qui est peu infesté par SOLEL. 

Figure 1 - Localisation des trois Champs Ecoles Paysans en Tunisie 

La planification des CEP a démarré dès novembre 2008 et les rencontres se sont étalées tout 

au long du cycle biologique de SOLEL de mars à novembre 2009. Environ 75 agriculteurs et 

techniciens du Ministère de l‘Agriculture, la Pêche et les Ressources Hydrauliques ont participé 

à ces rencontres qui ont regroupé à chaque fois : 

1-2 responsables techniques régionaux, 

2-3 techniciens vulgarisateurs locaux, 

Le coordinateur national du TCP, 

Le consultant national du TCP, et 

Une vingtaine d‘agriculteurs. 



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Le programme d‘activités de ces CEP était axé sur les thèmes suivants : 

Identification de SOLEL à ses différents stades de croissance, 

Exploitation des caractéristiques bio-écologiques de SOLEL dans sa gestion, 

Analyse des pratiques actuelles de lutte contre SOLEL (arrachage, labour, sarclage, etc.), 

et 

Evaluation des nouvelles pratiques de lutte contre SOLEL (sarclage, herbicides, cultures 

étouffantes, compostage). 

Les participants se sont rencontrés au moins 7 fois, tout au long du cycle biologique de 

SOLEL, à raison de 3 à 4 heures par rencontre. 

Les nouvelles pratiques évaluées sont : 

Comparaison des différents types de charrues (à disques, à pattes d‘oie et à lames), 

Comparaison des différents traitements herbicides (glyphosate et glufosinate), 

Comparaison de deux types de pulvérisations (manuelle et tractée), 

Comparaison de deux luzernières, 

Evaluation pratique de la technique de co-compostage de SOLEL avec le fumier et les 

déchets organiques. 

Résultats et Discussion 

Installation des CEP 

Les premières rencontres ont permis de constater que les agriculteurs des CEP de Jelma et 

Sbikha sont très préoccupés par SOLEL qui s‘avère très nuisible et difficile à maîtriser par les 

pratiques classiques de désherbage. Les agriculteurs pensent qu‘ils sont incapables de faire face à 

ce fléau et ils sollicitent le soutien du gouvernement pour maîtriser cette mauvaise herbe. A 

Mahdia, la situation était différente, puisque SOLEL est peu répandue et n‘est présente à des 

seuils inquiétants que chez très peu d‘agriculteurs. Ceci explique le peu d‘intérêt qu‘accordent 

les agriculteurs à SOLEL dans cette zone. Les participants ont souligné la nécessité de 

l‘intervention de l‘Etat pour maîtriser la situation avant qu‘elle ne devienne plus inquiétante et 

difficile à cerner. 

Caractéristiques bio-écologiques de SOLEL 

La majorité des participants aux CEP de Jelma et Sbikha était familiarisée avec SOLEL, vu 

son abondance et sa nuisance agronomique. La situation était un peu différente pour les 

participants au CEP de Mahdia où l‘espèce commence à déranger un petit nombre d‘agriculteurs. 

Peu de participants de Mahdia étaient capables d‘identifier correctement la plante. Quant à son 

origine géographique, plusieurs agriculteurs pensent qu‘elle provient d‘autres régions du pays et 

ignorent qu‘il s‘agit d‘une PEE. L‘ignorance de son statut handicape sa gestion, car il est 

inopportun de gérer les PEE comme les plantes nuisibles. En effet, le meilleur moyen de gestion 

des PEE est la prévention de leur introduction et de leur établissement dans un nouveau territoire. 

Concernant sa première apparition dans leurs champs, les agriculteurs n‘étaient pas unanimes ; 

certains pensent qu‘elle est présente depuis des dizaines d‘années et d‘autres ne l‘ont observée 

que depuis quelques années. Par ailleurs, la majorité des participants savait que SOLEL se 

multiplie végétativement et se reproduit sexuellement mais ils sont incapables d‘exploiter cette 



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information dans sa gestion puisqu‘ils se contentent des pratiques de lutte classiques contre les 

plantes nuisibles, notamment le labour et l‘arrachage manuel. 

Contrôles manuel et mécanique de SOLEL 

Les échanges entre les participants sur leurs pratiques actuelles de lutte contre SOLEL ont mis 

en évidence les conclusions suivantes : 

Les participants pensent que SOLEL est très difficile à contrôler par les pratiques 

conventionnelles (arrachage, sarclage à la sape, sarclage à la charrue, etc.) et ils attendent 

l‘homologation d‘herbicides en mesure de contrôler efficacement et durablement cette 

espèce. 

Certains agriculteurs pensent que les pratiques conventionnelles sont en mesure de 

maîtriser cette espèce, si elles sont appliquées avec acharnement dès son introduction. 

L‘analyse de ces pratiques nous a permis de constater ce qui suit : 

Les agriculteurs labourent les terres infestées par SOLEL, sans aucun encadrement 

technique : ils utilisent des charrues inadaptées à la lutte contre les vivaces, interviennent 

tardivement, et ne renouvellent pas assez souvent ces pratiques. 

Les agriculteurs pratiquent l‘arrachage et le sarclage manuels en début de saison estivale 

et les abandonnent dès que l‘exploitation de leurs cultures devient peu rentable. 

L‘arrachage et le sarclage manuels de SOLEL sont très répandus chez les petits paysans 

qui pratiquent une agriculture vivrière. 

Les pratiques actuelles ont favorisé la propagation et la dissémination de SOLEL. 

L‘évaluation de l‘entretien mécanique des terres (jachère et vergers) fortement infestées par 

SOLEL avec deux sarcleurs (pattes d‘oie ou pattes d‘oie et lames) a permis aux participants de 

constater ce qui suit : 

Le sarcleur à pattes d‘oie n‘arrache pas tous les pieds de SOLEL. En général, les 

sarcleurs à trois rangs sont plus efficaces que ceux à deux rangs. 

Le sarcleur combiné (pattes d‘oie et lames) arrache la quasi-totalité des plants de SOLEL. 

Il est très efficace sous des climats chauds et secs et sur sols bien nivelés, meubles et 

moyennement infestés. 

Durant la période estivale et en absence d‘irrigation, le sarclage mécanique peut réprimer 

efficacement SOLEL durant 4-6 semaines. 

Les sarclages à la herse combinée ont donné de très bons résultats. En effet, deux 

sarclages ont suffit pour affaiblir SOLEL et empêcher sa fructification. Ces sarclages 

étaient accompagnés d‘un sarclage manuel aux pieds des arbres. En général, 4-6 

croisements sont nécessaires pour prévenir la production de semences et épuiser les 

réserves des organes souterrains. Toutefois, en absence de pluie et d‘apport d‘eau 3-4 

croisements peuvent suffire. Il est possible d‘appliquer 2-3 sarclages jusqu‘à la fin de 

l‘été et d‘appliquer un traitement herbicide à la suite des premières pluies d‘automne. 

Les sarclages en été permettent de conserver l‘eau du sol et d‘assurer ainsi un bon 

démarrage des cultures automnales. Deux sarclages mécaniques, durant la période 

estivale, d‘une jachère fortement infestée par SOLEL ont permis de: (i) minimiser la 

fructification de SOLEL, (ii) épuiser ses réserves souterraines et (iii) préserver les 

réserves hydriques du sol. Ainsi, l‘agriculteur a profité des premières pluies d‘automne 



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pour semer de l‘orge sur cette parcelle. Au mois de novembre, les participants aux CEP 

ont constaté une faible infestation du site et un bon établissement de la culture. 

Techniques culturales 

Les échanges entre les participants sur la lutte intégrée contre SOLEL ont permis de constater 

que la majorité des agriculteurs n‘a aucun plan de lutte contre cette plante en Tunisie, ce qui 

explique sa propagation dans les champs. On peut résumer les pratiques actuelles de lutte contre 

SOLEL comme suit : 

Le choix des cultures et leur installation ne tiennent pas compte du degré d‘infestation 

des parcelles par SOLEL. Par exemple, les cultures fourragères sont pratiquées selon les 

besoins des éleveurs et non pour lutter contre SOLEL. 

Dans les cultures maraîchères, les seuls moyens de lutte sont les sarclages manuel et 

mécanique et l‘arrachage. Généralement, les maraîchers nettoient les parcelles et 

négligent leurs bordures et ces pratiques sont négligées dès que l‘exploitation des cultures 

devient peu rentable. 

Plusieurs maraîchers s‘approvisionnent en fumier à partir des zones infestées et aucun 

agriculteur ne pratique le compostage du fumier avant son épandage au champ. 

Dans les vergers, la lutte est axée sur le labour 1-2 fois par saison. Souvent, les 

interventions sont peu efficaces, voire même favorables à la propagation de SOLEL. 

La lutte dans les jachères est quasi absente car elles sont exploitées pour le pâturage des 

ovins. D‘ailleurs, ce mode d‘exploitation des terres a certainement contribué à la 

dissémination de SOLEL. 

L‘analyse de ces pratiques de lutte montre clairement que les agriculteurs n‘ont aucun plan de 

lutte contre SOLEL et que les pratiques actuelles sont souvent peu efficaces, voire même 

favorisent sa dissémination. Un des objectifs des CEP était d‘envisager de nouvelles pratiques, 

telle que l‘établissement de luzernières dans les parcelles fortement infestées par SOLEL. Mais 

certains agriculteurs étaient sceptiques à l‘idée de réprimer SOLEL par la luzerne. Pour 

permettre aux agriculteurs de juger eux même de l‘intérêt de la luzerne, deux luzernières ont été 

installées vers la fin du mois de mai dans des parcelles fortement infestées par SOLEL, une à 

Sbikha et l‘autre à Jelma. L‘agriculteur de Sbikha a raté l‘installation de la luzernière car il a 

négligé son irrigation et le contrôle des mauvaises herbes. Il estimait inutile de contrôler les 

mauvaises herbes dans une culture fourragère. Il a par ailleurs expliqué le manque d‘irrigation de 

la luzernière par des problèmes techniques. L‘agriculteur de Jelma, a quant à lui réussi 

l‘installation de sa luzernière car il a arraché manuellement SOLEL. Les agriculteurs habitués à 

cette culture savent bien qu‘il est indispensable de soigner son implantation pour garantir une 

répression efficace et pérenne de SOLEL. Par ailleurs, il a été recommandé de privilégier 

l‘installation de la luzerne au cours de l‘automne car au printemps SOLEL est très compétitive et 

peut freiner l‘établissement de la luzerne si elle n‘est pas contrôlée systématiquement tout au 

long de l‘été. Cette expérience nous a permis de confirmer la capacité de la luzerne d‘étouffer 

SOLEL, dès sa deuxième année d‘établissement. 

Contrôle chimique de SOLEL 

Les échanges entre les participants sur la lutte chimique contre SOLEL permettent de mettre 

en évidence les constats suivants: 

Les agriculteurs de Jelma n‘ont jamais utilisé d‘herbicides contre SOLEL. 



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Certains agriculteurs de Sbikha ont utilisé occasionnellement des herbicides et même du 

pétrole pour combattre SOLEL mais sans grand succès. 

A Mahdia, SOLEL n‘est pas très répandue dans les parcelles et les agriculteurs n‘ont par 

conséquent pas d‘expérience avec les herbicides. 

La majorité des participants attendent une solution chimique pour contrer SOLEL mais 

ils ignorent que la lutte chimique contre SOLEL ne peut être satisfaisante que si elle est 

pratiquée selon un plan pluriannuel et en combinaison avec d‘autres méthodes de lutte. 

A ce jour, la lutte chimique contre SOLEL est très peu répandue en Tunisie. D‘ailleurs, aucun 

herbicide n‘est homologué contre cette espèce. Habituellement, les herbicides sont peu utilisés 

dans les régions semi-arides. Cette situation a certainement contribué à favoriser la dissémination 

de SOLEL. 

L‘essai sur le terrain d‘herbicides à base de glyphosate et de glufosinate a permis aux 

participants de constater ce qui suit : 

Un traitement par saison à base de glyphosate est insuffisant pour réprimer durablement 

SOLEL. 

Le glyphosate est plus efficace contre SOLEL quand il est appliqué à une faible dose (1-1,5 

kg/ha), avec une fréquence de 2-3 traitements par saison, alors que son efficacité est 

courte s‘il est appliqué une fois par saison à dose complète (2-3 kg/ha). 

Un mois après l‘application des traitements, le glufosinate (Basta) était plus performant que 

le glyphosate (Round up Plus). Mais la reprise de SOLEL après les premières pluies 

d‘automne était plus vigoureuse dans la parcelle traitée avec le glufosinate. 

Co-compostage du fumier, de SOLEL et des déchets organiques 

L‘objectif principal de cette activité était de vulgariser la technique de co-compostage pour 

valoriser le fumier et les déchets organiques des exploitations agricoles et de détruire les 

semences de SOLEL. 

Les participants n‘étaient pas très familiarisés avec la technique de compostage comme 

moyen de : (i) valoriser le fumier et les déchets organiques des exploitations agricoles, et (ii) 

limiter la dissémination de SOLEL. Cette activité était une occasion pour se rappeler que le 

fumier ovin est un facteur important de dissémination de SOLEL et d‘apprendre que le cocompostage 

du fumier avec SOLEL, provenant des chantiers de désherbage manuel, peut être 

une technique très utile dans la lutte intégrée contre cette mauvaise herbe. En effet, le cocompostage 

permet de monter la température du fumier à plus de 60 þC et de provoquer ainsi la 

mortalité des semences de SOLEL et d‘autres semences de mauvaises herbes. 

Rencontre des CEP 

L‘objectif principal de cette rencontre était de favoriser les échanges d‘expériences entre les 

agriculteurs des trois CEP et de sensibiliser les agriculteurs et les techniciens des régions peu 

infestées aux dangers potentiels de SOLEL et des PEE. 

Evaluation des CEP 

La rencontre d‘évaluation des CEP, du 24 novembre 2009, a permis de constater que la 

formule originale des CEP, telle qu‘elle a été conçue en Indonésie et appliquée en Asie et en 



246

Afrique sub-saharienne n‘est pas bien adaptée à la mentalité des agriculteurs des régions de 

Kairouan, Sidi-Bouzid et Mahdia. En effet, au lieu de discuter entre eux, les agriculteurs 

préfèrent discuter avec les personnes ressources. De plus, même s‘ils sont conscients que SOLEL 

a atteint des niveaux d‘infestation inquiétants, ils expriment souvent d‘autres préoccupations, 

telles que l‘électrification des puits de surface et les prix des intrants agricoles. Pour faire face à 

cette PEE, ils utilisent les méthodes classiques de désherbage des cultures. En général, ces 

méthodes permettent de minimiser les pertes de rendements tant que les parcelles sont peu 

infestées mais sont incapables d‘arrêter l‘invasion de SOLEL. Les agriculteurs comptent 

beaucoup sur l‘Etat pour résoudre ce problème. 

Malgré ces difficultés, les CEP ont permis de tester et de valider de nouvelles techniques de 

lutte contre SOLEL en Tunisie (herbicides, sarcleurs à lames, luzernières, et co-compostage). 

Cette expérience a été très fructueuse et elle nous a amené à recommander : 

d‘adapter la formule originale des CEPs au contexte tunisien. 

de favoriser les programmes de lutte concertée contre SOLEL au sein des collectivités 

locales, des Associations à Intérêt Collectif (AIC), etc. 

d‘envisager l‘éradication de SOLEL dans les régions peu infestées. 

d‘adopter la technique de sarclage mécanique avec un sarcleur combiné (pattes d‘oie + 

lames) pour l‘entretien des jachères et des vergers tout au long de la saison chaude dans 

les terres fortement infestées. 

d‘homologuer des herbicides contre SOLEL. 

de généraliser la technique de co-compostage pour valoriser le fumier et les déchets 

organiques et limiter la dissémination de SOLEL. 

d‘encourager l‘établissement des luzernières dans les parcelles fortement infestées. 

Remerciements 

Les auteurs tiennent à remercier tout le personnel du bureau sous régional de la FAO pour 

l‘Afrique du Nord, de la Direction générale de la Protection et du Contrôle de la Qualité des 

Produits agricoles, des Commissariats Régionaux de Développement Agricole de Kairouan, 

Mahdia et Sidi Bouzid, et des cellules territoriales de vulgarisation de Jelma, Sbikha, Essouassi, 

Ksour Essef, et Mahdia. Particulièrement, ils remercient Messieurs Ezzeddine Chalgaf, Béchir 

Saida, Belgacem Omri et Tayeb Jelayli. 

Références 

Boyd JW, Murray DS & Tyrl RJ (1984) Origine, distribution et relation à l‘homme de la morelle jaune, Solanum 

elaeagnifolium. [in English] Economic Botany 38, 210-216. (en anglais) 

Braun A, Jiggins J, Röling N, van den Berg H and Snijders P (2006) A Global Survey and Review of Farmer Field 

School Experiences. Report prepared for the International Livestock Research Institut, Endelea, Rietveldlaan, 

3 6708 SN Wageningen, The Netherlands. 

http://www.infobridge.org/asp/documents/1880.pdf [accédé le 27 juillet 2010] 

Mekki M (2006) Potential threat of Solanum elaeagnifolium Cav. to the Tunisian fields. Invasive Plants in 

Mediterranean Type Regions of the World, pp. 235–242. Environmental Encounters Series No. 59, Council 

of Europe Publishing. Atelier international sur les plantes envahissantes des régions de type méditerranéen, 

25-27 mai 2005, Mèze (Hérault), France. 

Mekki M (2007) Biologie, Distribution et Impacts de la morelle jaune, Solanum eleaeagnifolium. [in English] 

OEPP/EPPO Bulletin 37 (1), 114-118. (en anglais) 



247

Outcomes of the Tunisian Experience on Farmer Field School Management of an invasive 

species Solanum elaeagnifolium 

Silverleaf nightshade (Solanum elaeagnifolium Cav. # SOLEL) is thought to be native to the 

South-Westem USA and Northern Mexico. It has spread to many arid regions of the world. The 

Food and Agriculture Organization of the United Nations (FAO) supported a regional 

programme (TCP/RAB/3102) on management of exotic invasive weeds, in particular SOLEL. 

This programme was effective in Morocco and Tunisia from July 2008 to December 2009. 

Several options for management of SOLEL have been evaluated in three Farmer Field Schools 

(FFS) located at two heavily infested regions (Kairouan and Sidi Bouzid) and a recently infested 

one (Mahdia). FFS involved about 75 farmers and technicians and an average of seven 

meetings/FFS. The treated subjects were: 

SOLEL identification to prevent its establishment in non infested areas, 

SOLEL biology as a tool for its practical management, 

Cultural and hand weeding options against SOLEL, 

Alfalfa ability to suppress SOLEL, 

SOLEL control with herbicides, 

Manure composting to kill SOLEL seeds and prevent its spread. 

These FFS were an occasion to enhance farmer‘s capacity to analyze SOLEL control methods, 

identify their restrictions, test possible solutions and eventually adopt the most suitable practices. 

Several options have given adequate results. Therefore, it is evident that an integrated 

management approach will be needed against SOLEL. 



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Legislative, biological and agronomic measures to comply with the Bern Convention 

recommendation n141/2009 on "Potentially invasive alien plants being used as biofuel 

crops" by Contracting Parties in the Mediterranean Basin 

Roberto Crosti 

ISPRA- Dipartimento Difesa della Natura-Tutela biodiversità, Via Curtatone 3 00185 ROMA, 

Italy. E-mail: roberto.crosti@isprambiente.it 

Recently the Standing Committee of the Council of Europe Convention on the Conservation of 

European Wildlife and Natural Habitats (Bern Convention), worried that the increase of biofuel 

cropping systems may lead to escapes from cultivation of invasive alien taxa with subsequent 

negative effect on native biological diversity, adopted a recommendation (n. 141) for Contracting 

States on ―Potentially invasive alien plants being used as biofuel crops‖. Loss of biodiversity, 

caused by escaped aggressive crops cultivars competing/crossbreeding with native species and 

causing impacts on natural habitats, is an important issue (together with food security, loss of 

soil fertility and land changes) to take into consideration to ensure sustainable bioenergy 

production. Several biofuel species, have traits in common with invasive species and may harm 

both the agroecosystems biodiversity (i.e. harming native hedgerows, semi-natural and remnant 

vegetation) and functionality (i.e. obstructing river channels or reducing the harvest yield). These 

crop species, being selected for broad ecological amplitude, rapid growth, high seed production, 

vegetative spread, resistance to pests and diseases are, in fact, potentially invasive. Furthermore, 

in farmlands habitat modification or degradation due to fragmentation, distorted water balance 

and nutrient cycle, altered fire regimes and abandonment of arable lands might contribute to the 

establishment of invasive taxa in new or temporarily ―vacant niches‖. Planting massive 

quantities of vigorous plant varieties on a large scale by repeated introductions, in different 

climates and soil conditions increases the propagules pressure and likelihood of ―crop escape‖, 

with subsequent, establishment of new biological invaders. This conference paper exemplifies 

which are the appropriate actions that Bern Convention Contracting Parties should undertake to 

be able to comply with recommendation n. 141. To reduce the potential risk of invasiveness 

(applying the precautionary principle) it is important to avoid the use of crops species which are 

already recognised as invasive elsewhere and to undertake a pre-cultivation screening on 

potential invasiveness for each proposed genotype and region. In addition the cropping system 

needs to consider the possibility of reducing propagules occurrence and dispersal even if this will 

effect agronomic and economic efficiency. Between the crop field and natural vegetation there is 

the need to interpose a buffer zone (i.e. made with non invasive crops) that acts as a biological 

barrier. The extension of the zone needs to be calibrated according to the invasiveness capacity 

of the crop. In addition, considering the fact that in the near future biofuel algae will be selected 

or engineered to increase photosynthetic efficiency, biomass productivity and survival in open 

ponds, farming and processing need to be undertaken in full containment in order to avoid any 

risk of environmental contamination. 



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Biomass crops in the Mediterranean: can experiments in Languedoc-Roussillon help to 

characterize the risk of invasiveness of the plants used? 

Pierre Ehret 

Ministère de L'Alimentation, de l'Agriculture et de la Pêche, Sous-Direction de la Qualité et de 

la Protection des végétaux, DRAAF/Service Régional de l'Alimentation, Maison de l'Agriculture, 

Place, Antoine Chaptal, CS 70039, 34 060 Montpellier Cedex 02, E-mail : 

pierre.ehret@agriculture.gouv.fr 

Introduction 

Increasing scarcity and cost of fossil fuels and the challenge of reducing CO2 

emissions influence proactive policies promoting renewable energy in Europe. 

Energy crops are part of the portfolio renewable energy and are providing an 

evenly and diversified supply of biomass that can be used for heating and 

power production. 

The Languedoc-Roussillon faced important changes in agriculture that led to 

the uprooting of vineyards and liberated land for cultivation. The use of 

agricultural land to produce energy crops has resulted in various projects 

implementing production or experimentation plots that are testing cropping 

systems developed in other climates, under the Mediterranean constraints. 

Exotic trees and shrubs are used in various soil and climatic conditions, mainly 

in short or very short rotation coppice in order to find the desired species with 

high production potential that can withstand the long summer dry period and 

provide enough biomass to be economically viable despite harsh agronomic 

conditions. 

As some plots are already established, it is necessary to propose protocols for 

monitoring the biology of the exotic species that are used in order to 

characterize their potential risk to express invasive characters. It might be a 

good opportunity to establish contacts with the biofuel industry to prepare a 

better risk mitigation of a new potential source of invasive plants. The Trabzon 

workshop gives an opportunity to share this new concern for the Mediterranean 

climate part of France. 

Crop-based biofuel production is developing in France, as in many other European countries, 

in response to increasing scarcity and raising cost of fossil fuels with the aim to reduce CO2 

emissions. Besides traditional crops like rapeseed (Brassica napus var. napus L.), sunflower 

(Helianthus annuus L.) or grain, used for ethanol or bio-diesel production, non-food crops used 

for cellulose production are also being developed. These are traditional annual crops harvested in 

whole plant form (such as triticale - ×Triticosecale Wittm. ex A. Camus), conventional forage 

crops (alfalfa - Medicago sativa L., fescue - Festuca L.), new perennial crops harvested annually 

(Miscanthus Andersson, switchgrass -Panicum virgatum L., etc.) or short rotation coppices of 

known woody species (poplar - Populus sp., Eucalyptus sp., etc.). 



250

Table 1- list of trees getting support to farming under the common agricultural policy when 

used in agricultural land for short rotation coppice, in France 

Botanical name Status 

Acer pseudoplatanus Native 

Alnus glutinosa Native 

Betula pendula Native 

Carpinus betulus Native 

Castanea sativa native or acclimated since the 

development of agriculture 

Eucalyptus gunnii and Eucalyptus Exotic 

gundal (E. gunnii x dalrympleana) 

Fraxinus excelsior Native 

Prunus avium Native 

Populus sp. native or exotic 

Quercus rubra Exotic 

Robinia pseudoacacia Exotic 

Salix sp. mainly native 

Sequoia sempervirens Exotic 

Many researches, field trials or development of small to medium scale plantations in relation 

with energy production companies already take place. Most of these crops are well known or 

documented as non-invasive. 

Before 2010, the monitoring of biofuel crop development was not considered as a priority by 

the French NPPO, in the framework of a still emerging activity related to invasive alien plants 

risk mitigation. 

Information gathered in the beginning of 2010 shows that a farmer in the north east of France 

is planting a cultivar of Reynoutria sacchalinensis (F.Schmidt) Nakai, a plant known for its high 

invasion capacity 5 . 

This kind of cultivation has highlighted the need for a better knowledge of this new activity 

(LNPV, 2010), in accordance with the EPPO Council recommendation on plants for renewable 

energy (EPPO, 2007). 

Potentially invasive plants are not currently regulated in France because they do not qualify as 

quarantine pests as defined within the European Union quarantine regulation, and because they 

were not yet evaluated by a national risk assessment system. The organisation of such a system 

has to be defined between the Ministry in charge of the Environment and the Ministry in charge 

of Agriculture. 

5 The cultivar, called « Igniscum » is promoted as non invasive, but no precise information on the biology of the 

plant as been found at this time. 



251

Many on-going biofuel projects try to assess the acceptance or the relevance of fuel crops 

from an energy, social, economic or environmental standpoint. A first broad survey on the 

Internet publication of these projects shows that the environmental aspects mainly focus on CO2 

balance or biomass combustion, but have only limited references to biological invasion concern 

when they deal with exotic species. 

The presentation of the outcomes of a project called CULIEXA (Nguyen, 2009) in April 2010 

in southern France, gave the NPPO the opportunity to make contact with researchers and 

extension workers in charge of biofuel projects and to get informed about a new project 

conducted by the "Chambre d'Agriculture de l'Aude". 

The Mediterranean region in France: climate and soil constraints for biofuel production, 

but available land and demand for energy 

The department of Aude is located between the Mediterranean Sea and the Pyrenees 

mountains, and is a part of the region Languedoc-Roussillon. The department is under the 

influence of a Mediterranean climate, but has several contrasts in climate: mountainous climate 

influences due to altitude, oceanic influence with heavier precipitation in the west, while in the 

east the climate is purely Mediterranean. It is one of the windiest French departments, with 300 

to 350 days of wind per year, which promotes installation of many wind turbines and the 

presence of companies developing decentralised energy production. 

Wine production is the main agricultural production of the department, and vineyards covered 

more than 85 000 ha in the beginning of the years 2000 and only more than 72 000 ha in 2008 

(Agreste, 2010). The shift of the demand of wine types and the incentives to uproot some of the 

vineyards, make agricultural land available for other cropping systems. 

The Chamber of Agriculture has decided to put in place trials of a broad range of perennial 

plants that could be used for biomass production. Beside woody or cellulosic species that can be 

burnt, other species, harvested with more leaves and higher water content were chosen in order 

to be added to waste in biogas production systems. The global aim is to propose plants and 

sustainable production systems for future biofuel solutions that can fit to strongly Mediterranean 

influenced climates and farming systems. 

Seven places were selected in locations representing the diversity of soils and climates of 

cultivated areas of the department and 30 plants species are or will be planted between the end of 

2009 and the end of 2010. The choice of the species (5 annual grasses, 4 perennial grasses and 21 

woody shrubs or trees) was made through expert judgment of the extension workers of the 

chamber, after discussion with the nursery industry and horticulturists. The knowledge of the risk 

related to the invasive character of some exotic species causing economic and environmental 

damage was taken into account for some well documented species, like Cortaderia selloana 

(Schult. & Schult. f.) Asch. & Graebn., which was not selected for the trials, despite of the well 

appreciated characters of rapid growth and easy propagation. 



252

Table 2 –Initial information gathered from a literature search on the exotic plants selected for 

the trials 

Species DAISIE 

(Present 

on the 

database) 

ISI Web of 

Knowledge SM 

(Number of 

references/research 

on species name and 

the term invasiv*) 

Global Weed Compendium 

Status(es) compiled Number 


referenc 

es in 

Atriplex canescens No 12 

GWC 

agricultural weed, naturalised, 8 

weed 

Atriplex nummularia Yes 3 cultivation escape, naturalised, 11 

noxious weed, weed 

Eucalyptus gunii x No 0 / 0 

dalrympleana 

clones) 

(gundal 

Eucalyptus gunnii Yes 3 6 

casual alien, cultivation escape, 4 

naturalised 

Eucalyptus 

dalrympleana 

No 1 7 

casual alien, naturalised 2 

Gleditsia triacanthos Yes 22 agricultural weed, casual alien, 39 

cultivation escape, 

environmental weed, garden 

thug, naturalised, noxious 

Panicum virgatum Yes 32 

weed, weed 

agricultural weed, casual alien, 15 

(Switchgrass) 

naturalised, weed 

Paulownia tomentosa Yes 16 casual alien, cultivation escape, 20 



Photinia x fraseri No 0 

weed, sleeper weed, weed 

/ 

0 

Photinia glabra 

Photinia serrulata 

No 0 / 

No 0 naturalised, weed 

Rhus lancea No 1 agricultural weed, 

environmental weed, 

naturalised, noxious weed, 

Robinia pseudoacacia 100 worst 

IAS 

weed 

89 agricultural weed, casual alien, 

cultivation escape, 



weed, sleeper weed, weed 

Rosa banksiae No 0 naturalised, weed 2 

6 references on insect gal present on this species 

7 reference on Phytophtora present on the species 



0 

6 

6 

19 

253

Monitoring propagule spread and biology of biofuel crops in new cropping system 

The project provided an opportunity to look at the literature concerning the weedy potential of 

proposed new biofuel crop species (Buddenhagen 2009, CAST 2007, Crosti 2009, CSIRO 2010), 

and it was clear that the exotic grasses, shrubs or trees that are proposed for the trials in order to 

find the desired species with high production potential that can withstand the long summer dry 

period and provide enough biomass to be economically viable despite harsh conditions might fit 

the ideotype of an invasive plant. 

The only species selected for the trial in France that is documented in the ongoing EPPO 

prioritization process for invasive alien plants in France (Fried, 2010) is Robinia pseudoacacia 

L., a widely used and promoted exotic tree. Most of the other species are less documented, and 

their biology in cropping systems for biofuel needs to be better known. 

Table 2 shows that their might be some concern about the invasive capacity of some of the 

species planted, but proposing a ban or delay for experimentation would have been neither 

pragmatic nor acceptable, first of all because the introduction of non-native species for 

horticultural or agronomic purposes is not regulated in France. 

As it is promoted by EPPO in horticulture, the involvement of the producers who are growing 

biofuel crops could be a useful way to prepare a regulation or a code of conduct to restrict the 

sale and distribution of species and cultivars that pose quantifiable threats to native species and 

ecosystems. 

One interesting first step will be to work with the extension services involved in the trials in 

order to monitor the propagule dissemination and biology of biofuel crops in the new cropping 

systems that are tested. This has still to be prepared, along with the gathering of available data on 

the biology of the various species involved. The knowledge already available in other 

Mediterranean type climates and countries might provide useful insights. 


Many thanks to Frédéric Prigent, from the chamber of agriculture de l'Aude, for his 

welcoming of these additional activities related to his trials, and to Guillaume Fried, from the 

Laboratoire National de la Protection de Végétaux, for his help for access to scientific databases. 

References 

Agreste (2010) Mémento régional Languedoc-Roussillon 2009 – La viticulture 

http://agreste.agriculture.gouv.fr/IMG/pdf_R9109C04.pdf [accessed on 28 July 2010]. 

Buddenhagen CE, Chimera C & Clifford P (2009) Assessing Biofuel Crop Invasiveness: A Case Study. PLoS ONE 

4(4): e5261. doi:10.1371/journal.pone.0005261 

http://www.plosone.org/article/info:doi/10.1371/journal.pone.0005261 [accessed on 28 July 2010] 

The Council for Agricultural Science and Technology (CAST) (2007) Biofuel Feedstocks: The Risk of Future 

Invasions. CAST Commentary QTA 2007-1. CAST, Ames, Iowa 

http://www.fs.fed.us/ficmnew/documents/notices/Biofuels2007.pdf [accessed on 28 July 2010] 

Crosti R (2009) Invasiveness of biofuel crops and potential harm to natural habitat and native species,- final version 

- Convention on the conservation of European wildlife and natural habitats and native species. Conseil de 

l'Europe , Strasbourg 

CSIRO (2010) Biosecurity in the new economy, OCDE Forum, 24 p. 

http://www.csiro.au/resources/2009-Biosecurity-Symposium-Booklet.html [accessed on 28 July 2010] 



254

EPPO (2007) Council recommendation on plants for renewable energy and Invasive Alien Plants 

http://www.eppo.org/STANDARDS/position_papers/bioenergy.htm [accessed on 28 July 2010] 

Fried G (2010) Prioritization of potential invasive alien species in France, 2nd International Workshop Invasive 

Plants in the Mediterranean Type Regions of the World 2010-08-02/06, Trabzon, Turkey (in these 

proceedings) 

LNPV (2010) Evaluation du risqué simplifié pour le cultivar Igniscum de la Renouée de Sakhaline, 10 p. 

N'guyen The N (2009) CULIEXA - Analyse des déterminants techniques et socioéconomiques au développement 

des cultures de biomasse ligneuse dans les exploitations agricoles 

http://www.fondation-tuck.fr/pdf/2009/resume1-NGUYEN-THE-Culiexa.pdf [accessed on 28 July 2010] 



255

Managing alien plant invasions: the role of restoration – Insights from South Africa 

Mirijam Gaertner 1 , Patricia M. Holmes 2 & David M. Richardson 1 

1 Centre for Invasion Biology, Department of Botany and Zoology, Stellenbosch University, 

Private Bag X1, Matieland 7602, South Africa 

2 Cape Ecological Services, 23 Dreyersdale Road, Bergvliet, 7945, South Africa 

Email: gaertnem@sun.ac.za*, rebelo@telkomsa.net, rich@sun.ac.za 

*corresponding author 

Introduction 

Invasions can reduce ecosystem resilience - ―the magnitude of disturbance that 

a system can absorb before it changes to alternative (stable) states‖. If 

resilience is reduced below a certain threshold the system will change to an 

alternative state. Alternative ecosystems can shift (often very abruptly) 

between two or more states and may have dynamics that are fundamentally 

different from those of pristine ecosystems. The trajectory to recovery will 

therefore differ in unpredictable ways from a pristine state to a degraded state. 

If the invaded ecosystem reaches a certain degree of degradation it might shift 

to a hybrid or even to a novel ecosystem state; depending on the interactions 

between biotic and abiotic changes triggered by invasive species. 

Traditional restoration practices have focused on re-establishing ―historic‖ 

disturbance regimes and biotic and abiotic conditions. However, in view of the 

significant changes caused by invasive species, new approaches recognize the 

existence of alternative (stable or transient) ecosystem states. The aim of this 

paper is to highlight the growing challenges in restoring ecosystems affected by 

invasive alien plants, to illustrate a framework for restoring ecosystems 

degraded by invasions adopting concepts of alternative states, thresholds and 

novel ecosystems, and to identify new questions and research needs for the 

development of a general framework for restoring ecosystems affected by alien 

plant invasions. 

Restoration is an integral part of managing invasive alien plants. Many restoration projects 

focus almost exclusively on the removal of species that are considered to have ―degraded‖ an 

ecosystem in some way. In many cases the removal of alien species is an important element in 

achieving other goals such as recovery of endangered species or repair of ecosystem function. 

However, in some cases, invasive species removal has become a goal in itself. Many restoration 

efforts have succeeded in mitigating negative impacts of invasive species, with important 

benefits. However, restoration efforts often have unforeseen consequences that sometimes even 

exacerbate rather than mitigate the ―problem‖ that triggered the restoration effort. Several factors 

that account for these unforeseen consequences have been identified. 

Firstly, biological invasions can cause major changes in ecosystem composition, structure and 

functions. These changes often lead to a decrease in ecosystem resilience. Resilience is defined 

by ―the magnitude of disturbance that a system can absorb before it changes stable states‖ 



256

(Gunderson, 2000). The degree of resilience of an ecosystem is an important measure for 

restoration ecologists as it defines the ability of an ecosystem to return to a state or condition 

which is still consistent with its former functions and feedbacks (Walker & Salt, 2006). Invasions 

can reduce the resilience of an ecosystem to a point where restoration to a former state is very 

difficult or practically impossible. The concept of ecosystem thresholds has been identified as a 

helpful tool to determine the degree of ecosystem degradation. An ecosystem threshold is the 

point where the maximum level of species resilience to degradation is reached. In the case of 

biological invasions, resilience can be reduced through the alteration of biotic factors (e.g. 

changes of species composition) and/or abiotic changes (e.g. changed nutrient cycles). If biotic 

changes and abiotic changes occur in concert a two-threshold model (introduced by Hobbs & 

Norton (1996)) can be adopted. The first threshold is reached when biotic interactions within 

communities change. This is sometimes followed by a second threshold after a longer timeframe 

of degradation. This second threshold is harder to reverse and can either be caused by amplified 

biotic interactions or by abiotic changes or a combination of the two (Suding & Hobbs, 2009). In 

a later stage of degradation invasives may alter the ecosystem in their own favour, and thus 

increase the rate of invasions (positive feedback loop). If positive feedback loops occur, a third 

threshold may be crossed – we therefore refer to the ―three-threshold model‖ of invasions. 

Changes to ecosystems often persist well after the removal of the invasive species. These so 

called ‗legacy effects‘ can cause increasing problems for restoration following invasion. 

Secondly, if the resilience of an ecosystem is reduced below a certain threshold, the ecosystem 

may shift between alternative stable states. Dynamics of invaded ecosystems (in terms of 

structure, functions and feedbacks) may consequently be different from those of pristine 

ecosystems and the trajectory to recovery might differ in unpredictable ways from that of the 

degradation (Suding et al., 2004). Traditional restoration efforts are based on the assumption that 

a sudden change in one direction (in this case provoked by alien invasion) can be reversed, and 

that some form of intervention can direct the system in the opposite direction to the forces of 

degradation (towards a more natural state) (Suding & Hobbs, 2009). The assumption was that 

alteration to ecosystems can be predicted, controlled and reversed. The intuitive management 

recommendation in terms of alien invasions was therefore to reduce the disturbance by clearing 

the alien species and to re-initiate recovery by sowing seeds of native species. However, these 

management strategies often failed as ecosystem conditions had already changed beyond 

thresholds and resulted in alternative states (Firn et al., 2010). Inappropriate management often 

results in ―secondary invasions‖ - the rapid replacement of the removed invasive species by 

others that capitalize on the disturbance caused by the control operations and/or resource 

alteration caused by the invasive species. Thirdly, if the invaded ecosystem reaches a certain 

degree of degradation it might shift to a hybrid or even novel ecosystem state. According to 

Hobbs et al. (2009) hybrid ecosystems result if a system experiences some changes (obtaining 

novel elements) but nevertheless retains original characteristics. For most of the hybrid systems 

restoration remains feasible. A system which experiences larger changes comprising different 

novel species combinations, interactions and functions can be defined as novel ecosystem. In a 

novel ecosystem changes are unlikely to be returned to a previous state because of the presence 

of restoration thresholds. Another challenge is that invasive species management can also 

degrade ecosystems and negatively affect native species. In some cases alien species invade by 

infiltrating ecosystem networks, notably pollination and dispersal networks and food webs, 

where they forge novel functions. Removal of these alien species can cause trophic collapses. 

Restoration efforts can also be compromised by conflicts of interest, for example in situations 



257

where invasive species provide habitat for rare native species. Such examples point to the need 

for more careful consideration of all implications of planned control and restoration programs. 

So far challenges in dealing with the restoration of invaded ecosystems have been identified 

(Zavaleta et al., 2001) and theoretical models engaging with these challenges are in place (e.g. 

Hobbs, Higgs & Harris, 2009; e.g. Suding & Hobbs, 2009). However, the implementation of 

these new approaches raises many questions and research needs. Here we (1) highlight 

challenges in restoring alien invaded ecosystems; (2) using Acacia invasions, we illustrate a 

framework for restoration of ecosystems degraded by alien invasions adopting concepts of 

alternative states, thresholds and novel ecosystems; and (3) identify questions and research needs 

for a framework for restoration after alien invasion. 

Managing alien plant invasions: challenges and unforeseen consequences 

Invasions reduce ecosystem resilience 

Biological invasions are increasing in importance as drivers of degradation, causing many 

types of impacts in ecosystems (e.g. Levine et al., 2003; e.g. Parker et al., 1999). Some manifest 

at the level of populations or communities, whereas others, usually at later stages of invasion, 

may produce impacts at the ecosystem level or even at higher trophic levels. Impacts of alien 

invaders not only have major implications for biodiversity and ecosystem function, but also 

greatly complicate restoration efforts by reducing the resilience of ecosystems (Richardson et al., 

2007). Reduction in ecosystem resilience due to alien invasions can be triggered by biotic 

interactions: For example, upon invading an ecosystem, invasive species may initially reduce 

resilience by changing community composition and structure and/or species diversity. Gooden et 

al. (2009) showed that Lantana camara L. invasion in New South Wales (Australia) reduced 

native species richness significantly once a certain threshold was reached: below an abundance 

of 75% cover of Lantana camara native species richness remained stable, but declined rapidly 

above this threshold level. Depending on the type of ecosystem invaded and the identity of the 

invading species, biotic changes can be followed and/or accompanied by abiotic changes (i.e. 

accumulation of nutrients). Abiotic changes include alterations of nutrient cycles (Marchante et 

al., 2008; Rossiter-Rachor et al., 2009; Yelenik et al., 2004) and increased water use (Le Maitre 

et al., 1996), another concern is increased erosion in alien invaded habitats (Reed et al., 2005). 

Positive feedback loops and alternative ecosystem states 

The most frequent scenario however, is that alien invasions change biotic and abiotic 

conditions in concert to create positive feedback loops. Positive feedbacks occur when the 

ecosystem response is to change a variable even more in the same direction, driving the system 

away from its original state; eventually resulting in a directional shift to an alternative state 

(Suding & Hobbs, 2009). Positive feedback loops can be triggered by competitive advantage of 

invasive species, for example Phalaris arundinacea invasions cause rapid shifts from diverse 

native vegetation to a Phalaris monotype (Healy & Zedler, 2010). Positive feedback loops 

initiated by the creation of nutrient cycling patterns that favour the invader have been extensively 

investigated (Ehrenfeld et al., 2001; Kulmatiski et al., 2008; Liao et al., 2008). For example 

Chrysanthemoides monilifera ssp. rotundata, an evergreen shrub native to South Africa, causes 

alterations in nutrient cycling in Australian dune ecosystems in favour for their survival but at 

the expense of native species (Lindsay & French, 2005). Other invasive species alter ecosystem 

properties to facilitate the establishment of their seedlings. Siemann and Rogers (2003) showed 



258

that Chinese tallow trees (Triadica sebifera) established in grasslands in the southern United 

States can indirectly favour their seedlings in competition with neighbouring herbaceous 

vegetation through changes in resource levels (through increased soil fertility and reduced light 

levels). An emerging area of interest is the positive feedback loops that are initiated by altered 

microbial processes brought about by invasions (Reinhart & Callaway, 2006; Vogelsang & 

Bever, 2009; Wolfe & Klironomos, 2005). Sanon et al. (2009) investigated positive feedbacks 

exerted by Amaranthus viridis through alterations of microbial activities (combined with changes 

in nutrient cycling) in Senegal. The results suggest a significant negative effect on the growth of 

native Acacia species. A change in fire regime is a positive feedback loop which has been 

suggested to be the most important cause of large scale ecosystem alterations (Brooks et al., 

2004; D'Antonio et al., 2000). Especially invasive grasses create positive feedback loops by 

increasing fire frequency and altering fire intensity, often changing habitats previously 

dominated by woody plants into grassland (Rossiter-Rachor et al., 2008; Rossiter et al., 2003). 

However, invasive species can also reduce fire frequency (e.g. Stevens & Beckage, 2009). Since 

positive feedback loops frequently forge novel functions; unpredictable responses may occur 

even after invasive species disappear following control efforts. These so called legacy effects are 

for example soil-nutrient changes caused by invasive species which often persist after their 

removal (Marchante et al., 2008; Maron & Jeffries, 2001; Yelenik et al., 2007). This persistence 

may hamper the restoration of native communities for a long period. Moreover, it has been 

suggested that symbionts (i.e. mycorrhizal fungi) may have the capacity to survive after 

eradication of the alien plant and to extend into native ecosystems establishing symbiosis with 

native species potentially out-competing native symbionts (Diez, 2005). Another critical concern 

for restoration is that these legacies of invasive species often cause secondary invasions of other 

weedy species (Zavaleta, Hobbs & Mooney, 2001). 

Framework for restoration of ecosystems degraded by alien invasions 

In managing degraded ecosystems we have to accept that (1) ecosystems occur in alternative 

stable states; and that (2) the dynamics of degradation may differ from that of recovery. The first 

step in a restoration project is therefore to classify the state of ecosystem degradation (i.e. to 

determine the probability that an ecosystem will respond to an invasion event in a defined way) 

and, where appropriate, to identify novel ecosystem dynamics. The second step involves 

evaluating different restoration strategies. The last step is to decide which type of intervention is 

appropriate. This decision will not only depend on the degree of degradation of the ecosystem 

but also on the conservation value of the ecosystem and other practical considerations (e.g. 

availability of resources). 

Resilience, alternative states and options for restoration – a case study of Acacia invasion in 

South Africa 

As an example, we consider the case of invasions by Australian Acacia species in South 

Africa‘s Cape Floristic Region (CFR). The CFR is a biodiversity hotspot (Myers et al., 2000) 

with more than 9000 plant species being found in a relatively small area (ca. 90 000 km 2 ) (Bond 

& Goldblatt, 1984). Alien invasions pose a serious threat to the region‘s biodiversity, and 

Australian Acacia species are among the most widespread and damaging invaders. Several 

species have a huge invasive potential and strong persistence due to the production of massive 

loads of long-lived seeds (Richardson & Kluge, 2008). Dense invasive stands radically increase 



259

iomass and change fuel properties and therefore fire behaviour in fynbos ecosystems (van 

Wilgen & Richardson, 1985). Alien Acacia species also alter the nutrient dynamics of fynbos 

systems by radically increasing nitrogen levels (Yelenik, Stock & Richardson, 2004). Thus 

projects focusing on the restoration of Acacia invaded sites encounter a variety of problems. 

Firstly, soil nutrient changes can persist after the removal of Acacia species and may hamper the 

restoration of native communities for a long period (Yelenik, Stock & Richardson, 2004). 

Autogenic recovery following Acacia clearing is therefore considered to be little successful with 

extensive regeneration of alien species but only a negligible recovery of indigenous species 

(Reinecke et al., 2008). Secondly, Acacia invasions cause a significant reduction in native seed 

bank density and richness, it has hence been suggested to include the re-introduction of native 

species into restoration strategies following Acacia invasions (Holmes & Cowling, 1997). 

However, the competitive advantage of fast growing Acacia species in combination with 

changed nutrient levels inhibits the re-establishment of native species. Thirdly, the high 

longevity of the extensive Acacia seed bank is a major obstacle for its successful control 

(Richardson & Kluge, 2008). 

We suggest that restoration of areas invaded by Australian Acacia species could be 

substantially improved by considering the concepts discussed above. This will involve: 

1. Exploring extent to which extent ecosystem resilience has been reduced and 

whether thresholds have been reached; 

2. Defining likely ―alternative‖ states; and 

3. Considering different options for restoration. 

At the early stage of invasion Acacia species may change biotic structural components (e.g. 

altered native species composition). With increasing duration of invasions these changes in biotic 

structure result in alterations of biotic functions (i.e. suppression of native species). The 

dominance of Acacia species and the decrease of native species numbers and abundances will 

reduce ecosystem resilience. After a certain duration of invasion, a threshold will be reached; 

beyond this the system will change to an alternative state. Native species composition and 

structure are changed and the native seed bank may be depleted. This state can be defined as a 

hybrid state; although biotic components have been altered, the system is still capable of 

autogenic recovery if the stressors (invasive acacias) are removed, as long as key abiotic 

components are intact (Figure 1, B). 

As the invasion duration increases, biotic changes will be accompanied by abiotic structural 

changes (i.e. shading and accumulation of soil nitrogen). Impacts on the native ecosystem might 

be increased competition for light or altered soil nitrogen availability. This can lead to further 

reductions of native species abundances and/or numbers – a second threshold is reached. At this 

stage native community composition and structure are severely affected and the community will 

be dominated by Acacia species. We would still refer to this as a hybrid state. Restoration at this 

stage needs to adopt strategies to reverse the abiotic changes. Until now, restoration strategies 

have involved mechanical clearing of the invasive plants, burning and sometimes sowing of 

native species. One problem that has been experienced is the secondary invasion of alien 

herbaceous species but also a rapid recovery of Acacia species. Following the approach of Firn et 

al. (2010) other control strategies based on the alternative states model will need to be 

implemented to successfully reduce Acacia invasions (Figure 1, C). If structural and functional 



260

changes of biotic and abiotic components cause positive feedback loops (i.e. increased soil 

nutrient levels lead to enhanced growth of Acacia species) a third threshold will be reached: 

Acacia species will form monocultural stands suppressing any growth of native species. Positive 

feedback loops will most likely create thresholds for restoration; in this case the system has 

shifted to a novel ecosystem. Restoration of a novel ecosystem will be very difficult (although 

not impossible). Here the high conservation value of the CFR will definitively influence decision 

making. Whether restoration to a ―natural‖ state is possible or not will obviously depend on 

available resources. However, management should at least include clearing of the invaded areas 

to prevent spread to other regions. Crucial, especially with the massive seed producing Acacia 

species, is the reduction of the soil seed bank. Among other options preventing the accumulation 

of seed bank by limiting seed production through biological control is by far the most effective 

strategy reducing seed numbers (Richardson & Kluge, 2008). Because of the high number of rare 

and endemic species in the CFR restoration to a state as close to natural as possible should be the 

paramount objective for restoration (Figure 1, D). However, when an ecosystem reaches a novel 

state such as ‗D‘ (extreme alteration in structure and functions) it is unreasonable to set 

restoration goals that strive to attain a pristine or near-pristine ecosystem state. 

Low 

degradation/ 

recent 

invasion 

High 

degradation/ 

long invasion 

Native Hybrid Novel 

A 

Biotic 

threshold 

B 

Abiotic 

threshold 

Bioticabiotic 

feedback 

threshold 

positive 

feedbacks 

Figure 1: Three-threshold model (modified from Whisenant 2002) illustrating the concept of 

thresholds which indicate break points between alternative ecosystem states: (A) native 

ecosystem state, no threshold reached (e.g. altered species composition but aboveground 

vegetation and/or seed banks intact); (B) hybrid ecosystem state, biotic threshold is reached 

(e.g. altered species composition and structure, seed bank depleted); (C) hybrid ecosystem 

state abiotic and biotic thresholds are reached (e.g. altered water and nutrient availability); (D) 

positive feedbacks trigger threshold to be reached (e.g. changed abiotic functions favor the 

growth of invasive species but causes extinctions of native species). 



C 

D 

261

Evaluation of restoration strategies – which intervention is appropriate in which situation 

Our example refers to a particular region which is acknowledged as biodiversity hotspot; 

restoration of the ecosystem to a state as close as possible to historic conditions would usually be 

first priority. As resilience theory argues that this (restoration to historic conditions) is 

impossible (due to pervasive human-mediated modifications and effects of climate change etc) 

an alternative approach is to define a value-based ‗desired state‘ and to deduce the desired 

ecosystem state from that (Rogers & Bestbier, 1997). (In other situations (e.g. if the conservation 

importance of the system is not of paramount importance) deciding on the restoration 

intervention will depend on other considerations such as the functions and services that could 

potentially be provided by the ecosystem in the future. Although studies on invasions mainly 

report negative impacts of invasions on the native ecosystem (e.g. Gaertner et al., 2009; Hejda et 

al., 2009; Yurkonis et al., 2005), invasive species may also have positive impacts, by providing 

certain ecosystem functions. If invasive species invade on ecosystem long enough they can get 

integrated into native ecosystem networks providing functions of native species which have been 

either replaced or even extinct (Affre et al., 2010). In such cases restoration practitioners need to 

consider whether removal of the invader will largely or even entirely remove a function from 

that system which has become necessary for other biota (Zavaleta, Hobbs & Mooney, 2001) or 

(pragmatically) desirable, in terms of the future use of the ecosystem in question. In certain 

pollinator networks for instance alien plants serve as resources for pollinators where native 

plants have gone extinct (Graves & Shapiro, 2003; Severns & Warren, 2008). In other cases alien 

plant species might provide a usable habitat for native species, the most prominent example 

probably being invasive salt cedar (Tamarix sp.) in riparian ecosystems in the south-western 

United States (Shafroth et al., 2005). In some situations invaders can even facilitate the growth 

of native species. Rodriguez (2006) reviewed different mechanisms of facilitation including 

habitat modification, trophic subsidy, pollination, competitive release, and predatory release. 

Habitat modification was the most frequently documented mechanism, in other cases invasive 

species provide a limiting resource, increase habitat complexity, functionally replace a native 

species, or ameliorate predation or competition. 

To summarise: In determining appropriate restoration strategies and deciding on a suitable 

type of intervention one has to consider the degree of ecosystem degradation and the 

conservation value of the ecosystem. Furthermore, ecosystem services and functions of the 

degraded ecosystem have to be evaluated and traded against negative impacts of invaders. Last 

but not least, economical considerations (i.e. prioritisation of investment) also play an important 

role. To provide a framework for decision making, we categorized the different steps and 

summarised them in Figure 2. 

Research needs 

We present a preliminary outline of a scheme for adopting concepts of alternative ecosystem 

states, resilience and thresholds, and novel ecosystems into a framework for the restoration of 

ecosystem degraded by invasive species. We acknowledge and emphasize that our framework 

can only be regarded as a starting point. For further development of this framework and 

especially for its implementation we will need to address the following questions: 

1. Although studies on impacts (and the underlying mechanisms) of plant invasions are 

manifold, specific investigations on ecosystem resilience and thresholds are scarce (but see 



262

Gooden et al., 2009). How do we determine the degree of resilience of an ecosystem? Which 

ecosystem properties will give an indication of its resilience? What are the links between 

resilience and diversity (or species richness) of an ecosystem? How do we determine whether an 

ecosystem has reached a threshold and changed from its original state to an alternative state? 

2. Although studies by Hobbs et al. (2009) provide some guidelines for the distinction 

between hybrid and novel ecosystems, the difference between the two types remains somewhat 

arbitrary. Hobbs et al. (2009) suggest that the classification of an ecosystem as hybrid or novel 

depends on the trajectory of ecosystem change away from the historic configuration. These 

trajectories are largely based on whether biotic and abiotic changes occur separately or in 

concert. In some degraded ecosystem this distinction might be easy to make. However, with 

alien invasions biotic and abiotic changes are sometimes difficult to separate. 

3. If an ecosystem is defined as ―novel‖, the decision on whether to restore or not will often 

create conflicts of interest between different conservation groups. Here, more information is 

needed on the adverse effects of destructive invasive species and the positive impacts of some 

invasive species which may be lost if the invader is removed. 

4. The notion of ‗alternative states‘ appears to suffer from different and possibly conflicting 

interpretations coming from resilience theorists and restoration theorists. A review of the 

philosophical origins and development of different sets of interpretations will provide a 

fundamental contribution to an improved understanding of the framework offered here. 

5. The framework suggested could provide powerful motivation for investment early 

detection and rapid response (EDRR). The implications of EDRR for state changes and 

restoration is therefore an extremely exciting avenue for further study. 

Native ecosystem 

degradation 

Hybrid ecosystem = restoration feasible 

biotic changes 

biotic and abiotic changes 

positive feedback loops occur 

Ecosystem is able to autogenic recovery after 

invasives have been removed 

Determine appropriate restoration 

strategies based on alternative state 

model (e.g. Firn et al. 2010) 

Novel ecosystem= restoration thresholds occur: restoration will only be 

possible with major input of significant management resources 

Region of 

conservation value 

Region of low 

conservation value 

If sufficient resources are available, restore as 

close as possible to natural state. If resources are 

insufficient control invasives to avoid further 

spread. 

Consider ecosystem services provided by 

invasives, maximise beneficial changes and 

reduce less beneficial aspects. Control invasives 

to avoid further spread. 

Figure 2: Framework for the restoration of ecosystems degraded by alien invasions 

(following the concept of novel ecosystems developed by Richard Hobbs et al. (Hobbs et al., 

2006; Hobbs, Higgs & Harris, 2009). 



263

Conclusions 

Restoration ecologists dealing with ecosystems degraded by alien plant invasions are facing a 

variety of challenges including legacies and secondary invasion after alien species control, 

unexpected outcomes of control operations and conflicts of interest between different 

stakeholders. Although new and exciting concepts to tackle these challenges are in place, the 

implementation thereof is still pending (but see Firn, House & Buckley, 2010; but see Gooden et 

al., 2009). We suggest that combined efforts of sharing knowledge and conducting research and 

its implementation between restoration ecologists, resilience ecologists and theorists and 

invasion biologists could provide answers to open questions and help to control invaders more 

successfully. 

References 

Affre L, Suehs CM, Charpentier S, Vilà M, Brundu G, Lambdon P, Traveset A & Hulme PE (2010) Consistency in 

the habitat degree of invasion for three invasive plant species across Mediterranean islands. Biological 

Invasions 12, 2537-48. 

Bond P & Goldblatt P (1984) Plants of the Cape flora: A descriptive catalogue. South African Journal of Botany 13, 

1-13. 

Brooks ML, D'Antonio CM, Richardson DM, Grace JB, Keeley JE, DiTomaso JM, Hobbs RJ, Pellant M & Pyke D 

(2004) Effects of invasive alien plants on fire regimes. Bioscience 54, 677-88. 

D'Antonio CM, Tunison JT & Loh RK (2000) Variation in the impact of exotic grasses on native plant composition 

in relation to fire across an elevation gradient in Hawaii. Austral Ecology 25, 507-22. 

Diez J (2005) Invasion biology of Australian ectomycorrhizal fungi introduced with eucalypt plantations into the 

Iberian Peninsula. Biological Invasions 7, 3-15. 

Ehrenfeld JG, Kourtev P & Huang W (2001) Changes in soil functions following invasions of exotic understory 

plants in deciduous forests. Ecological Applications 11, 1287-300. 

Firn J, House APN & Buckley YM (2010) Alternative states models provide an effective framework for invasive 

species control and restoration of native communities. Journal of Applied Ecology 47, 96-105. 

Gaertner M, Den Breeyen A, Hui C & Richardson DM (2009) Impacts of alien plant invasions on species richness in 

Mediterranean-type ecosystems: A meta-analysis. Progress in Physical Geography 33, 319-38. 

Gooden B, French K, Turner PJ & Downey PO (2009) Impact threshold for an alien plant invader, Lantana camara 

L., on native plant communities. Biological Conservation 142, 2631-41. 

Graves SD & Shapiro AM (2003) Exotics as host plants of the California butterfly fauna. Biological Conservation 

110, 413-33. 

Gunderson LH (2000) Ecological resilience - in theory and application. Annual Review of Ecology and Systematics 

31, 425-39. 

Healy MT & Zedler JB (2010) Set-backs in replacing Phalaris arundinacea monotypes with sedge meadow 

vegetation. Restoration Ecology 18, 155-64. 

Hejda M, Pyšek P & Jarosik V (2009) Impact of invasive plants on the species richness, diversity and composition 

of invaded communities. Journal of Ecology 97, 393-403. 

Hobbs RJ, Arico S, Aronson J, Baron JS, Bridgewater P, Cramer VA, Epstein PR, Ewel JJ, Klink CA, Lugo AE, 

Norton D, Ojima D, Richardson DM, Sanderson EW, Valladares F Vila, M, Zamora R & Zobel M (2006) 

Novel ecosystems: Theoretical and management aspects of the new ecological world order. Global Ecology 

and Biogeography 15, 1-7. 

Hobbs RJ, Higgs E & Harris JA (2009) Novel ecosystems: Implications for conservation and restoration. Trends in 

Ecology & Evolution 24, 599-605. 

Hobbs RJ & Norton DA (1996) Towards a conceptual framework for restoration ecology. Restoration Ecology 4, 

93-110. 

Holmes PM & Cowling RM (1997) The effects of invasion by Acacia saligna on the guild structure and 

regeneration capabilities of South African fynbos shrublands. Journal of Applied Ecology 34, 317-32. 

Kulmatiski A, Beard KH, Stevens JR & Cobbold SM (2008) Plant-soil feedbacks: A meta-analytical review. 

Ecology Letters 11, 980-92. 



264

Le Maitre DC, VanWilgen BW, Chapman RA & McKelly DH (1996) Invasive plants and water resources in the 

Western Cape Province, South Africa: Modelling the consequences of a lack of management. Journal of 

Applied Ecology 33, 161-72. 

Levine JM, Vila M, D'Antonio CM, Dukes JS, Grigulis K & Lavorel S (2003) Mechanisms underlying the impacts 

of exotic plant invasions. Proceedings of the Royal Society of London Series B-Biological Sciences 270, 775- 

81. 

Liao CZ, Peng RH, Luo YQ, Zhou XH, Wu XW, Fang CM, Chen JK & Li B (2008) Altered ecosystem carbon and 

nitrogen cycles by plant invasion: A meta-analysis. New Phytologist 177, 706-14. 

Lindsay EA & French K (2005) Litterfall and nitrogen cycling following invasion by Chrysanthemoides monilifera 

ssp. rotundata in coastal Australia. Journal of Applied Ecology 42, 556-66. 

Marchante E, Kjoller A, Struwe S & Freitas H (2008) Short- and long-term impacts of Acacia longifolia invasion on 

the belowground processes of a Mediterranean coastal dune ecosystem. Applied Soil Ecology 40, 210-17. 

Maron JL & Jeffries RL (2001) Restoring enriched grasslands: Effects of mowing on species richness, productivity, 

and nitrogen retention. Ecological Applications 11, 1088-100. 

Myers, N, Mittermeier, R A, Mittermeier, C G, Da Fonseca, G A B & Kent, J (2000) Biodiversity hotspots for 

conservation priorities. Nature 403, 853-58. 

Parker IM, Simberloff D, Lonsdale WM, Goodell K, Wonham M, Kareiva PM, Williamson MH, Von Holle B, 

Moyle PB, Byers JE & Goldwasser L (1999) Impact: Toward a framework for understanding the ecological 

effects of invaders. Biological Invasions 1, 3-19. 

Reed HE, Seastedt TR & Blair JM (2005) Ecological consequences of C-4 grass invasion of a C-4 grassland: A 

dilemma for management. Ecological Applications 15, 1560-69. 

Reinecke MK, Pigot AL & King JM (2008) Spontaneous succession of riparian fynbos: Is unassisted recovery a 

viable restoration strategy? South African Journal of Botany 74, 412-20. 

Reinhart, K O & Callaway, R M (2006) Soil biota and invasive plants. New Phytologist 170, 445-57. 

Richardson DM, Holmes PM, Esler KJ, Galatowitsch SM, Stromberg JC, Kirkman SP, Pyšek P & Hobbs RJ (2007) 

Riparian vegetation: Degradation, alien plant invasions, and restoration prospects. Diversity and 

Distributions 13, 126-39. 


invasiveness and options for management. Perspectives in Plant Ecology, Evolution and Systematics 10, 161- 

77. 

Rodriguez LF (2006) Can invasive species facilitate native species? Evidence of how, when, and why these impacts 

occur. Biological Invasions 8, 927-39. 

Rogers KH & Bestbier RX (1997). Development of a protocol for the definition of the desired state of riverine 

systems in South Africa. Department of Environmental Affairs and Tourism, South Africa. 

Rossiter-Rachor NA, Setterfield SA, Douglas MM, Hutley LB & Cook GD (2008) Andropogon gayanus (Gamba 

grass) invasion increases fire-mediated nitrogen losses in the tropical savannas of northern Australia. 

Ecosystems 11, 77-88. 

Rossiter-Rachor, N A, Setterfield, S A, Douglas, M M, Hutley, L B, Cook, G D & Schmidt, S (2009) Invasive 

Andropogon gayanus (gamba grass) is an ecosystem transformer of nitrogen relations in Australian savanna. 

Ecological Applications 19, 1546-60. 

Rossiter NA, Setterfield SA, Douglas MM & Hutley LB (2003) Testing the grass-fire cycle: Alien grass invasion in 

the tropical savannas of northern Australia. Diversity and Distributions 9, 169-76. 

Sanon A, Beguiristain T, Cebron A, Berthelin J, Ndoye I, Leyval C, Sylla S & Duponnois R (2009) Changes in soil 

diversity and global activities following invasions of the exotic invasive plant, Amaranthus viridis L., 

decrease the growth of native sahelian Acacia species. Fems Microbiology Ecology 70, 118-31. 

Severns PM & Warren AD (2008) Selectively eliminating and conserving exotic plants to save an endangered 

butterfly from local extinction. Animal Conservation 11, 476-83. 

Shafroth PB, Cleverly JR, Dudley TL, Taylor JP, Van Riper C, Weeks EP & Stuart JN (2005) Control of Tamarix in 

the Western United States: Implications for water salvage, wildlife use, and riparian restoration. 

Environmental Management 35, 231-46. 

Siemann E & Rogers WE (2003) Changes in light and nitrogen availability under pioneer trees may indirectly 

facilitate tree invasions of grasslands. Journal of Ecology 91, 923-31. 

Stevens JT & Beckage B (2009) Fire feedbacks facilitate invasion of pine savannas by Brazilian pepper (Schinus 

terebinthifolius). New Phytologist 184, 365-75. 

Suding KN, Gross KL & Houseman GR (2004) Alternative states and positive feedbacks in restoration ecology. 

Trends in Ecology & Evolution 19, 46-53. 



265

Suding KN & Hobbs RJ (2009) Threshold models in restoration and conservation: A developing framework. Trends 

in Ecology & Evolution 24, 271-79. 

van Wilgen BW & Richardson DM (1985) The effects of alien shrub invasions on vegetation structure and fire 

behaviour in South African fynbos shrublands: A simulation study. Journal of Applied Ecology 22, 955-66. 

Vogelsang KM & Bever JD (2009) Mycorrhizal densities decline in association with nonnative plants and contribute 

to plant invasion. Ecology 90, 399-407. 

Walker BH & Salt D (2006) Resilience thinking: sustaining ecosystem and people in a changing world. Island Press, 

Washington D.C. 

Wolfe BE & Klironomos JN (2005) Breaking new ground: Soil communities and exotic plant invasion. Bioscience 

55, 477-87. 

Yelenik SG, Stock WD & Richardson DM (2004) Ecosystem level impacts of invasive Acacia saligna in the South 

African fynbos. Restoration Ecology 12, 44-51. 

Yelenik SG, Stock WD & Richardson DM (2007) Functional group identity does not predict invader impacts: 

Differential effects of nitrogen-fixing exotic plants on ecosystem function. Biological Invasions 9, 117-25. 

Yurkonis KA, Meiners SJ & Wachholder BE (2005) Invasion impacts diversity through altered community 

dynamics. Journal of Ecology 93, 1053-61. 

Zavaleta ES, Hobbs RJ & Mooney HA (2001) Viewing invasive species removal in a whole-ecosystem context. 

Trends in Ecology & Evolution 16, 454-59. 



266

A large-scale project of invasive plant coenosis control in Mediterranean sand coastal area: 

two case studies and a model to standardize the management criteria 

Antonio Perfetti 

Regional Park of Migliarino San Rossore Massaciuccoli, Manager of Nature Conservation 

Service, Palazzo degli Stalloni, Cascine Vecchie di San Rossore, I-56122 PISA, Italy. 

E-mail: a.perfetti@sanrossore.toscana.it 

Psammophilic coastal ecosystems are extremely limited in nature. In addition, they are also very 

selective for the species that live there. For these reasons the control of invasive alien plant 

communities gives a good opportunity to consider effectiveness on a larger scale area in respect 

to a cost-benefit framework. In this paper I analyze two case studies that concern 8 km of 

coastline and 80 ha of psammophilic vegetation. In this area there is a rich mosaic of 

phytocoenosis (13 habitats of conservation interest according to Habitat Directive definitions) 

where the Regional Park has carried out a complex restoration project with the control of 6 ha of 

alien coenosis of Amorpha fruticosa in the inter-dune wet habitat and the control of over 280 

patches of Yucca gloriosa scattered in the dune xeric habitat. A monitoring program before and 

post intervention clearly shows the changes with respect to the hydrogeological and biological 

environment. Finally, I discuss ecosystem benefits from a local and a strategic view and analyze 

the technique and the financial constraints to model and understand the key parameters and 

criteria to reduce errors and enhance effectiveness when planning this kind of interventions. 



267

Three tools to manage alien weeds in Swiss agricultural and non agricultural environments 

– a proposal 

Christian Bohren 

Research Station Agroscope Changins-Wädenswil ACW, route de Duillier, CH- 1260 Nyon, 

Switzerland, E-mail: christian.bohren@acw.admin.ch 

Introduction 

Information on alien weed species interfering in agricultural and non 

agricultural zones is manifold, but is always directed to a certain objective, 

with a certain background. Many leaflets on weeds might appear incomplete to 

the reader. General guidelines are needed to concentrate financial and human 

resources for invasive alien species. 

Three elements – a collection of weak point sheets for noxious native and 

invasive alien weed species, a list of costs for control methods and a list of 

restrictions for use of control methods in environmental zones, the latter 

adapted to a country – would allow any civil servant in any region to choose 

adequate control methods. 

Practical tools on the control of invasive and other noxious plant species are 

proposed. The first tool consists in a sheet per plant containing an exact 

description of the weak points in the life cycle of the species. A collection of 

sheets would address all species relevant for a certain region or country. The 

second tool is a list containing details on costs of machines, labour and 

additional efforts for control methods. This must be adapted to each country 

situation, and it must be updated regularly. The third tool is a list containing 

detailed information on restrictions – adapted to a region or country – for the 

use of herbicides or other control methods in all existing zones such as water 

surface, water lines, forest, traffic lines, public and private green, agricultural, 

horticultural, industrial and residential zones, unproductive zones in mountain 

areas and others. 

Men have been trading products since the beginning of civilisation. Weed seeds as 

contaminants in cereal grains have been displaced from the Middle East to Europe since the 

earliest beginning of cereal production. Farmers have been controlling native weeds in native 

crops – as well as alien (exotic) weeds in newly invented crops – since the beginnings of 

agriculture. Weeds have always been able to accommodate themselves to new crops and to new 

cropping techniques (Zwerger & Ammon, 2002). 

Plant invasions depend always on the life-form of the species, as well as on the type of land 

use and last but not least on the climate of the affected region (Hulme, 2009). Moreover the 

enemy release hypothesis (Elton, 1958) is based on the observation that invasive alien plants do 

intend to profit from reduced enemy (herbivore, fungal or viral pathogens) damage, as compared 

with the same species in its native range; species may possess traits that make them pre-adapted 

for invasion (Müller-Schärer & Schaffner, 2008). It is very difficult to predict the invasiveness of 

an exotic plant species. This impracticality to predict plant invasions often hampers a timely start 



268

of control measures. Information exchange is a key component for effective responses to 

biological invasions (Browne et al., 2009). 

Invasions are often detected only after the invader might be newly established. Therefore a 

complete eradication of an invasive plant species might be very difficult to impossible (Weber, 

2003). Control methods must aim at minimizing the impacts of an invader. Effective control 

strategies must be developed to minimize the spread and impact of invasive alien species (CBD, 

2011). 

Costs of control of invasive alien plants might be covered in most cases by public funds. Once 

control measures against a certain plant species have been initiated, a long term expenditure of 

money is foreseeable. Annual invasives cannot be controlled effectively in one year because of 

the seed bank in the soil; any short term control of perennials cannot be effective because of their 

strong reproductive ability. 

Time of reaction is an important factor increasing control costs. Public funding is always 

subject to political decisions; but for taking decisions politicians need to understand quickly the 

problem. Weed science must elaborate specific control information in the view of timely 

decisions. In addition, research is needed on the success of control methods. 

The objectives of this review are to present the actual situation of invasive alien plants in 

Swiss agriculture. Based on these experiences some conclusions are drawn in order to improve 

tools for a rapid response to plant invasions. 

Examples of species 

In Switzerland, 3 species are currently subject to intensive discussions and are abundant in 

agricultural areas: Ambrosia artemisiifolia, Solidago Canadensis and Cyperus esculentus 

(Bohren et al., 2008). 

Ambrosia artemisiifolia: This annual weed invades residential zones as well as agricultural 

zones. Several nationwide information campaigns informed the public on the highly allergenic 

pollen of the species via television, radio and newspapers. Around 12 % of the population is 

sensible to A. artemissifolia pollen and therefore concerned with the prevention of the species. 

An obligation to control A. artemisiifolia and to announce new findings of the species is legally 

anchored in the Swiss ordinance on plant protection (Bohren, 2006). Farmers and the general 

public need to know to recognize the weed and the possibilities to control it. Medical, ecological 

and agricultural specialists push continuously on effective control measures. A. artemisiifolia can 

be considered under control. 

Solidago canadensis: Solidago species are commonly used as ornamental plants. The 

available are the result of breeding and selection programs. The plants are long-lived and 

adaptable. The flowers vary in shade of yellow depending on cultivar and bloom in late summer 

or fall. Solidago is propagated by rhizomes and seeds. In Switzerland Solidago often invades 

roadsides as well as railways and abandoned construction areas (CPS-SKEW, 2011). The 

intensive yellow colour of the magnificent flowers is not associated with the danger of an 



269

invasive plant. The general public may not be easily convinced why this plant must be contained. 

Solidago invades wild flower strips which have been established on agricultural fields in the 

scope of the ecological compensation system (Bohren, 2010). The invasion of Solidago is going 

on. 

Cyperus esculentus is an aggressive perennial neophyte creating problems in vegetable and 

arable crops. It can be effectively managed with a consistent integrated control program that 

combines cultural, mechanical and chemical methods. It is troublesome in intensive vegetable 

production. In private gardening or public greens C. esculentus is neither troublesome nor well 

known. Actually C. esculentus only affects farmers; the number of populations has increased in 

the last couple of years. No public interest exists while it is necessary to control this neophyte. 

Cantonal agricultural services are busy advising farmers on how to control Cyperus (Strickhof, 

2011). 

Legal aspects 

The Swiss Commission for Wild Plant Conservation (CPS/SKEW) has elaborated factsheets 

on alien plants containing non legally-binding guidelines to control these species. The Federal 

Office for the Environment (FOEN) has amended the Release Ordinance (RO 814.911) with a 

list of Prohibited Invasive Alien Organisms containing 11 alien plants. Handling of these plants 

is forbidden; but there is no direct mandate to control these species. The cantons may decide to 

amend cantonal law for official control of invasive alien plants. In 2006 the Federal Office for 

Agriculture (FOA) has amended the Ordinance on Plant Protection (PSV 916.20) and declared A. 

artemisiifolia subject to official control (Bund, 2010), which forces farmers to control it. 

Cantonal agricultural advisory services are responsible to manage A. artemisiifolia in agricultural 

zones, but so far there is no federal legal base for the control of the other species listed. 

Needs 

There is lack of basic information on control know-how. For better understanding of control 

measures the weak points in the life cycle of a plant need to be identified. The weak points 

should always be the angle of attack of control measures. Politicians need facts to understand 

why rapid response is necessary and how it could be afforded. Practical users need facts in order 

to respond rapidly. Financial and human resources need to be invested usefully in recognized 

problems. 

Practical tools on rapid response to plant invasions especially in non agricultural areas are 

needed, and not only in Switzerland. Simple tools should enable authorities and politicians to 

create legally based guidelines for the control of invasive plants. Research is needed on the long 

term efficiency of control measures. 

Three Tools 

Alien Plants Weak point-factsheets: A proposal is to establish a one page sheet per species 

containing an exact description of its life cycle and its point of attack for efficient control ―weak 

point‖. Some general information on control measures might be simply described, such as 

uprooting, cutting, herbicide application, use of biological control agents and others. Basic 

information that will not be subject to changes in the future must be given. Consequences of 



270

incomplete control and reasons for failure of control measures should also be mentioned in the 

sheet. Then, the necessity of effective control measures and of post-treatments should be 

mentioned. Two examples are provided in tables 1 and 2. A collection of sheets would represent 

all species relevant for a certain region or country. 

Control Methods Expenses-list: The collection of sheets needs to be accompanied by a list 

containing details on costs of machines, labour and additional efforts to control the plant. This 

list would enable the user to estimate roughly the costs for control measures. The Swiss research 

station Agroscope ART publishes periodically a list of almost all costs relevant to the Swiss 

agriculture (Gazzarin et al., 2010). This list could be adapted to the needs of invasive plants 

control and be updated annually. 

Control Methods Restrictions-list: A second list needs to be established, containing detailed 

information on restrictions (adapted to a region or country) for the use of herbicides or other 

control methods in all existing zones, such as water surface, water lines, forest, traffic lines, 

public and private green, agricultural, horticultural, industrial and residential zones, unproductive 

zones in mountain areas and others. This list must be updated as need arises. 

Table 1: Example of text in a Weak point-factsheet for Fallopia japonica 

Weak point (point of attack for efficient control): 

Fallopia species multiply by small buds placed on the root system; 1 bud per 2 cm root length. 

Cut stem lying on wet and fertile ground produce roots and sprout; 1 bud per 15 cm 

Control method mechanical mechanical / chemical biological 

Questions and 

comments 

What is the most 

effective control 

method? 

Reasons for 

failure of control 

method? 

What type of 

post-treatment is 

necessary? 

excavating* 

ground (m 3 ) and 

cleaning* / 

disposal* of 

excavated material 

Uprooting* is not 

recommended 

because not all roots 

can be uprooted 

Efficacy of control 

is reduced if pieces 

of roots remain in 

the ground 

Sequence of cutting* in 

late spring and herbicide 

treatment* in early autumn 

as well as disposal of plant 

material* (compost) 

Cutting* solely is not 

recommended because of 

unsufficient efficacy; 

herbicide treatment* 

underlies various restrictions 

for environmental reasons 

Efficacy of control may be 

reduced by surviving plants 

(e.g. fast re-growth after 

cutting or insufficient 

herbicidal efficacy) 

Purchase* and release* 

of control agents* and 

disposal* of plant material 

A combination of 

biological control methods 

with mechanical / chemical 

methods is recommended 

Efficacy of control may 

be reduced by surviving 

plants (e.g. in case of 

unsufficient number of 

control agents) 

Efficiency control in the following year is always necessary; sequential control 

measures may be necessary 

*= see control method expenses list 



271

Table 2: Example of text in a Weak point-factsheet for Ambrosia artemisiifolia 

Weak point: Ambrosia survives winter as seed only. 

The plant must be destroyed before flowering and seed production. 

Control method mechanical mechanical / chemical biological 

Questions and 

comments 

What is the most 

effective control 

method? 

Comments: 

Reasons for failure 

of control method? 

What type of aftertreatment 

is 

necessary? 

Conclusions 

Mowing* with 

mower* or scythe* 

or trimmer* 

Uprooting by 

hand* effective in 

small stands; 

deposit* of plant 

material 

Mowing* and herbicide 

treatment* 

Mowing* solely is not 


unsufficient control; 

Herbicide treatment* solely is not 


ecological impact; combination of 

methods is recommended 



Purchase* and 

release* of control 

agents* (at present 

not available) 

A combination of 

biological control 

methods with 

mechanical / chemical 

methods is 

recommended 

The treated plant re-sprouts in case of incomplete control success and forms – even 

in reduced quantities – pollen and grains 

Efficiency control in the following year is always necessary; sequential control 

measures may be necessary 

Public authorities should provide a legal base for an effective control by promoting rapid 

response to newly invading plants; established invaders must be controlled where they cause 

damage to landowners. A weak point-factsheet should simply answer questions regarding 

prevention of species such as: which part of the plant needs to be destroyed; which type of 

propagules needs to be found and destroyed; how must the plant material removed be treated. 

Reasons for failure of control methods must be mentioned, and the type of post-treatment must 

be commented. All these data must be formulated so that the information cannot be outdated. 

Those types of fact sheets could be translated and used in other countries. 

The described three elements – a collection of weak point sheets for noxious native and exotic 

weed species, a detailed list of costs for control methods and a detailed list of restrictions for the 

use of control methods in environmental zones, both adapted to a country or region – would 

allow any civil servant to choose adequate control methods. It may be helpful for a rapid 

response to a plant invasion to know early enough which part of the plant need to be eliminated 

in order to break down the invasion. This information concept could work in every region or 

country. 

The Working Group on Invasive Plants of the European Weed Research Society (EWRS 

www.ewrs.org ) would provide a good network and a platform to elaborate the proposed type of 

weak-point factsheet and to distribute it. Local advisory services would elaborate and update an 

expenses-list. Local authorities would elaborate and update a restrictions-list. 

272

References 

Bohren C (2006) Ambrosia artemisiifolia L. – in Switzerland: concerted action to prevent further spreading. 

Nachrichtenblatt des deutschen Pflanzenschutzdienstes 58, 304-308. 

Bohren C, Delabays N & Rometsch S (2008) Invasive Pflanzen: Herausforderung für die Landwirtschaft? 

Agrarforschung 15, 314-319 (in German). 

Bohren C (2010) Exotic weeds contamination in Swiss agriculture and non agriculture environment – a review. 

Agronomy for Sustainable Development 

http://www.springerlink.com/content/w310264466h72kln/fulltext.pdf (accessed on 10 June 2011). 

Browne M, Pagad S & De Poorter M (2009) The crucial role of information exchange and research for effective 

responses to biological invasions. Weed Research 49, 6-18. 

Bund (2010) Ordinance of Plant Protection, SR 916.20, AS 2006/2531. Classified Compilation of Federal 

Legislation, Bern (CH). 

CBD (2011) Convention on Biological Diversity. COP 6 Decision VI/23. http://www.cbd.int/decision/cop/?id=7197 

(accessed on 10 June 2011). 

CPS-SKEW (2011) Commission suisse pour la conservation des plantes sauvages. http://www.cpsskew.ch/fileadmin/template/pdf/inva_deutsch/inva_soli_can_d.pdf 

(accessed on 10 June 2011) (in German 

and French). 

Elton CS (1958) The ecology of invasionsby animals and plants. Methuen, London (UK). 

Gazzarin C & Vögeli GA (2010) Maschinenkosten 2009/2010 ART Bericht 717, 

http://www.agroscope.admin.ch/data/publikationen/ART_Bericht_717_D.pdf (accessed on 10 June 2011) (in 

German). 

Hulme PE (2009) Relative roles of life-form, land use and climate dynamics of alien plant distributions in the British 

Isles. Weed Research 49, 19-28. 

Müller-Schärer H & Schaffner U (2008) Classical biological control: exploiting enemy escape to manage plant 

invasions. Biological Invasions 10, 859-874. 

Strickhof (2011) www.strickhof.ch (accessed on 10 June 2011). 

Weber E (2003) Invasive plant species of the world: a reference guide to environmental weeds. CABI Publishing, 

Cambridge (UK). 

Weber E, Köhler B, Gelpke G & Perrenoud A (2005) Schlüssel zur Einteilung von Neophyten in der Schweiz in die 

schwarze Liste oder die Watch-Liste. Botanica Helvetica 115, 169-194. 

Zwerger P & Ammon HU (2002) Unkraut – Ökologie und Bekämpfung. Eugen UlmerVerlag Stuttgart (DE) (in 

German). 



273

Biology and Control of Heterotheca subaxillaris (Camphor weed) in Israel 

Mildred Quaye 1 , Tuvia Yaacoby 1,2 and Baruch Rubin 1 

1 The Robert H. Smith Faculty of agriculture, Food and Environment, The Hebrew University of 

Jerusalem, Rehovot, 76110 Israel, E-mail: mildyq@yahoo.com 

2 Ministry of Agriculture and Rural Development, Plant Protection and Inspection Services, P. O. 

Box 78 Bet Dagan 50250 Israel 

Introduction 

Heterotheca subaxillaris (camphor weed) a dicotyledonous winter annual weed 

of the Asteraceae family, is a native to North America. The plant invaded Israel 

during the last 20 years occupying a wide range of habitats, rapidly infesting 

cultivated and non cultivated ecosystems such as orchards, nature resorts, range 

land, open fields, waste grounds, road sides and railroad embankments. We 

found that optimum germination occurs at 28/22þC (day/night) in both light 

and dark conditions, but high germination rate were recorded even at 34/28þC. 

Highest emergence (88%) was recorded when seeds were sown at a shallow 

depth (0-1cm) in sandy soil. However, less than half of the seeds emerged from 

the shallow depth (0-1cm) in the heavy (clay) soil while no seedlings emerged 

from deeper layers. H. subaxillaris is very sensitive to herbicides commonly 

applied in road sides and non-cultivated areas such as atrazine, diuron, 

sulfometuron and imazapyr at their appropriate recommended rates. In 

addition, trifloxysufuron, imazapyr and fluroxypyr applied post-emergence 

effectively controlled young seedlings (4-6 leaves stage), whereas paraquat + 

diquat, glyphosate and fomesafen were less effective as the injured plants 

recovered few weeks after treatment. No control of H subaxillaris was 

observed even when oxyfluorfen was applied post-emergence at the highest 

dosage (960g ai/ha). Our results indicate that H. subaxillaris can be managed 

with the existing pre- and some of the post- emergence herbicides as other 

cultural methods (mulching and tillage). 

Heterotheca subaxillaris (Lam.) Britton & Rusby (Camphor weed) is a dicotyledonous winter 

annual herb belonging to the Asteraceae family; it reproduces by seed and thrives well in sandy 

and disturbed soils (Baskin & Baskin, 1976). H. subaxillaris possesses a tap root system, grows 

to an average height of about 0.3 - 1.8 m and branches profusely near the ground. Depending on 

the time of germination and winter conditions, it may behave as a biennial weed (Awang & 

Monaco, 1978). The leaves having toothed margins are alternatively arranged along the hairy 

stem and contain characteristic camphor-like odor when crushed, giving the plant its vernacular 

name ‗camphor weed‘. H. subaxillaris is a self-incompatible species (Olsen, 1997), developing 

flower buds in summer and blooming during midsummer and fall. The plant produces two kinds 

of seed/achenes either from the ray (ligulate) or the disc (tubular) flower, and exhibits different 

size and germination characteristics (Baskin & Baskin 1976). The seeds produced from the 

ligulate flowers are dormant upon maturity, they do not germinate when dispersed as they 

undergo physiological after-ripening processes and may germinate only at high temperatures and 



274

under light conditions. The seeds developed from the tubular flower heads are not dormant when 

mature they germinate shortly after their dispersal in both light and dark conditions and under a 

wide range of temperatures. These characteristics exhibited by the seeds (germination 

dimorphism) serves as a survival mechanism for the species to have more than one chance of 

establishment in any particular habitat (Harper, 1965; Datta et al., 1970; Unger, 1971; Baskin & 

Baskin, 1988). 

Camphor weed, is an invasive alien species considered to be a native to North America (Grin, 

2000;) growing throughout the year in Israel and rapidly covering cultivated and non-cultivated 

land areas including orchards, open areas, range land, waste places, highways and railroad 

embankments (Yaacoby, 1998). H. subaxillaris competes with crops for space and nutrients and 

makes farming activities difficult. It possesses strong allelopathic properties that inhibit growth 

of other plants species by making the plant persistent in different habitats. Despite the invasive 

nature and rapid dispersal of its seeds, there has not been much recent account in literature 

concerning the biology, life cycle and methods for controlling this weed. This paper is therefore 

aimed at studying the biology and control of H. subaxillaris. 


Seeds of H. subaxillaris were collected from an open field in Rehovot on January 2009, and 

were cleaned by removing hair attached and other foreign material that might interfere with the 

germination process. 

Germination at constant and varying day/night temperatures 

In order to study the germination characteristics of H. subaxillaris with respect to the various 

growth conditions, four replicates of 20 seeds, each in light and dark conditions were sown in 9 

cm diameter Petri dishes lined with 2 layers of Whatman No 1 filter paper moistened with 4 ml 

of distilled water. For seeds to be germinated in the dark, the Petri dishes were wrapped with 

aluminum foil to prevent light penetration. The Petri dishes both covered and uncovered were 

then kept in the laboratory (25 þC) or in the various growth rooms (at the temperatures of 

34/28þC; 28/22þC; 22/16þC and 16/10þC) in the phytotron for 7 days and the daily number of 

germinated seed was recorded. Germination was determined by the protrusion of the radicle 

through the pericap as described by Sung et al., (2008). Another experiment was conducted in 

order to determine the contribution of ray and disc seeds to the proliferation of the weed species 

by sowing 20 seeds each of ray and disc types in four replicates under light and dark at 25 þC for 

7 days. 

To determine the influence of the soil types and depths on the germination and emergence of 

H. subaxillaris, twenty seeds were sown at 0, 1, 2, 3, 4, 5, 6 and 7 cm depths in both light (100% 

sand of Rehovot soil) and heavy (48.1% clay of Naan soil) soils in separate experiments. The 

experiments were terminated 8 WAT (weeks after treatment) when there were no further 

seedlings emergence. Emerged seedlings were counted and recorded. 



275

Pre and post emergence Herbicide treatments 

In these experiments we accessed the efficacy of the various pre and post-emergent herbicides 

on H. subixillaris. Commercial formulations of atrazine, diuron, oxyflourfen, fluridone, 

sulfometuron, and imazapyr which were to be applied at the following recommended rates 1000 

g ai/ha, 800 g ai/ha, 480 g ai/ha, 500 g ai/ha, 37.5 g ai/ha and 500 g ai/ha respectively were 

applied pre-emergence onto the soil surface of pots (7x7x8 cm containing 5 seeds each) using a 

chain driven sprayer at the these rates: atrazine (0, 500, 1000 and 2000 g ai/ha); diuron (0, 800 , 

1600 and 3200 g ai/ha); oxyfluorfen (0, 240, 480 and 960 g ai/ha); fluridone (0, 250, 500, and 

1000 g ai/ha); sulfometuron (0, 7.5, 37.5 , 150 g ai/ha) and imazapyr (0, 250, 500 and 1000 g 

ai/ha). A non-treated control (NTC) treatment was included in each herbicide. The treatments 

were done on the same day and kept under similar conditions in the screen house. 

Commercial formulations of glyphosate(480g ai/ha) oxyfluorfen(480g ai ha), paraquat + 

diquat(400g ai/ha), trifloxysufuron (7.5g ai/ha), fomesafen (625g ai/ha), imazapyr (500g ai/ha) 

and fluroxypyr (200g ai/ha) at the above recommended rates were applied post-emergence using 

a chain driven sprayer delivering 300L/ha to 4-6 leaves plants grown in pots as described above. 

These herbicides were applied at the following rates: glyphosate (0, 480 , 960 and 1920 g ai/ha); 

oxyfluorfen (0, 240, 480 and 960 g ai/ha); paraquat + diquat (0, 200, 400 and 1000g ai/ha); 

trifloxysufuron (0, 7.5, 15 and 30 g ai/ha); fomesafen (0, 250, 625 and 1250 g ai/ha); imazapyr 

(0, 250, 500 and 1000 g ai/ha) and fluroxypyr (0, 200 , 400 and 600 g ai/ha). Rate of damage 

was scored every other day after the treatment (DAT). The experiments were terminated 30 DAT 

and seedlings shoot weights were recorded. A non treated control (NTC) treatment was included 

in each herbicide. 

Statistical analysis 

Data were analyzed using the "Sigma Plot" software and Micro Soft Excel. The concentration 

of herbicides that inhibited 50% of weed growth (ED50) was calculated from the dose response 

equation. 

Fig. 1: Germination rate of unsorted (A) and sorted (B) seeds of H. subaxillaris exposed to 

light or dark at 25þC for 7 days. The data represent means ± SE of 4 replicates. 



276

Results 

Effect of constant or varying day/night temperatures on the germination of camphor weed 

Initial germination test conducted with unsorted and sorted seeds of H. subaxillaris showed a 

maximum germination percentages when seeds were sown in both light and dark at 25þC (Fig. 

1A). 80 and 70% of the disc seeds germinated in light and dark respectively, however, only 10% 

of the ray seeds germinated in light while no germination occurred in dark. 

High germination rates were recorded in all temperature regimes tested (34/28 þC; 28/22 þC; 

22/16 þC; and 16/10 þC) 7 DAT. Germination rates of 65% and 63% were observed during the 

second day at 28/22þC and 22/16þC respectively with seeds exposed to light (Fig. 2A). The rates 

increased till the fourth day when then no further germination was recorded. Similarly, high 

germination rates were recorded in the dark too, during the period of the second to the fifth days 

(Fig. 2B). 

Fig. 2: Germination rates of H. subaxillaris seeds in light (A) and dark (B) at varying 

day/night temperatures during 7 days. The data represent means ± SE of 4 replicates. 

We studied the effects of the various soil types and depths of sow on seedling emergence of 

camphor weed. In the sandy soil, 88% of the seedlings emerged from the shallow depth (0-1cm), 

29% from 2-3 cm depth and no emergence was observed from deeper treatments (4-5 and 6-7 

cm). (Fig 3 A). Fewer seedlings (45%) emerged at the shallow depth (0-1cm) in the clay soil and 

no seedling emerged when sown at 2-3; 4-5 and 6-7 cm depths (Fig. 3B). 

Effects of Pre and post emergence herbicide applications 

All herbicides applied pre-emergence reduced emergence rates and seedling growth of the 

weed. A rate of 898 g ai/ha of diuron reduced 50% of the seed germination and seedling growth, 

as well as 1.5 g ai/ha of sulfometuron (Fig. 4A). At twice the recommended rate (page 3) 



277

atrazine, oxyfluorfen and fluridone reduced seedlings Fresh weight of the weed by 100%. All 

herbicides applied post-emergence reduced more than 50% of the seedlings fresh weight, except 

oxyfluorfen which did not control the weed even when applied at a highest dosage (960 g ai/ha) 

(Fig. 4B). The different rates of injury observed at various intervals after treatment (DAT) show 

that paraquat + diquat reduced 90% of the weed growth at 3 DAT however, the plant recovered 

afterwards. (Fig. 5). 

Fresh shoot weight (% control) 

Fig. 3: Influence of soil type and sowing depths on the emergence of H. subaxillaris seedlings 

in sandy (A) clay (B) soils. 

120 

100 

80 

60 

40 

20 

0 

0.1 1 10 100 1000 10000 

Fig. 4: Response of H. subaxillaris to various herbicides applied pre- (A) and post- (B) 

emergence at different rates. 

Discussion 

Atrazine 

Diuron 

Oxyfluorfen 

Fluridone 

Sulfometuron 

Imazapyr 

Herbicide rate( g ai/ha) 

A 

Fresh shoot weight (% control) 

120 

100 

80 

60 

40 

20 

0 

Glyphosate 

Oxyfluorfen 

Paraquat +Diquat 

Trifloxysufuron 

Fomesafen 

Imazapyr 

Fluroxypyr 

0.1 1 10 100 1000 10000 

Herbicibe rate (g ai/ha) 

Our results shows that germination rates of 86% and 82% were recorded for one week old seeds 

exposed to 25þC under light and dark conditions respectively (Fig. 1A). Such high germination 

rates may be an indication of a higher germinability of seeds shortly after dispersal. A lower 

(10%) germination rate was recorded for ray seeds (Fig 1B). This result is consistent with Baskin 

& Baskin (1988) who concluded that ray seeds are dormant upon maturity, and hence will not 

germinate when dispersed. The optimal rate of germination was recorded at any day/night 

temperatures (34/28 þC ; 28/22 þC ; 22/16 þC ; and 16/10 þC) between 2 and 4 days in both light 



B 

278

and dark conditions. (Fig. 2A and 2B). The high germination rate in the very first days of seed 

dispersal could account for the tremendous increase in population size of the weed in any 

location within a short time after its establishment. This high germination rate in the first days of 

dispersal could also mean a higher growth rate that provides the weed an advantage over other 

weed species within the same location. This result conformed to Baskin & Baskin (1988) who 

reported rapid germination of the weed seeds shortly after dispersal. 

Control (%) 

100 

80 

60 

40 

20 

0 

Herbicides 

Day 3 

Day 6 

Day 9 

Fig 5. Estimated injury rate of H. subixillaris seedlings scored 3 to 21 DAT with various 

herbicides. 

The wide range of alternating day/night temperatures at which the seeds germinated in this 

experiment suggests that H. subaxillaris growth and development could be favoured in both 

warm and cold seasons. According to Awang & Monaco (1978), germination of H. subaxillaris 

occurs over a wide range of temperatures starting as low as 3þC, but this applies to disc achenes 

only, whereas ray achenes will only germinate under high temperatures. This may also explain 

the reason of persistent and continuous growth of the weed throughout the year in Israel. 

For most agricultural weed species, germination is initiated by seeds exposure to light. This 

however, varies from species to species as some will only germinate when exposed to light, 

while others will germinate in both light and dark conditions. Our results show an appreciable 

germination rate when seeds were exposed to both light and dark (Fig. 1A and B, 2A and B). A 

number of seeds germinate in the dark indicating that H. subaxillaris seeds will germinate even 

when the soil surface is covered with mulching material, or when seeds are buried into a shallow 

depth of soil. Although seeds germinated in the dark, the seedlings were weak and etiolated and 

hence might not develop healthy and competitive mature plants if compared to the plants 

emerged in light. Mulching therefore may help in managing this weed. 

Burial depths and soil types did affect the emergence of the seedlings in our experiment (Fig. 

3 A and B). As burial depth increase, the number of emerged seedlings decreased. An emergence 

percentage of 88% was recorded when seeds were sown at 0-1cm depth, 29% emerged at 2-3 cm 

depth, while no emergence was recorded at 4-5 and 6-7 cm depths in the sandy soil. In clay soil, 

Day 

12 



279

only 45% of seedlings emergence was found at the shallow depth (0-1cm), and no emergence 

was recorded when the sowing depth increased. Zhang & Maun (1994), concluded that 

emergence of seedling is directly related to the seed size and the depth at which seeds are buried. 

Excessive burial may prevent seedlings emergence and survival (Hue & Maun, 1999). These 

statements are true for the present findings as H. subaxillaris inability to emerge from a deeper 

depth might be due to its small seed size. A bigger seed means more energy reserve and hence 

greater vigor and higher chance for the seedlings to emerge from deeper depths (Waller, 1985). 

Table 1: ED50 (rate that caused 50% growth inhibition) values of different herbicides and 

their modes of action on H. subaxillaris. 

Herbicides ED50 (g ai/ha) Mode of action 

Glyphosate 537 Inhibition of EPSP enzyme 

Paraquat +diquat 162 Inhibition of PSI 

Trifloxysufuron 14 Inhibition of ALS enzyme 

Fomesafen 368 Inhibition of Protox enzyme 

Imazapyr 183 Inhibition of ALS enzyme 

Fluroxypyr 398 Disruption of plant cell growth 

Diuron 898 Inhibition of PSII 

Sulfometuron 1.5 Inhibition of ALS enzyme 

Imazapyr (pre- 

emergence) 

411 

Inhibition of ALS enzyme 

Similarly, lower emergence (45%) in the heavy soil (clay) even at the shallow depth may be 

attributed to the seed size which is unable to penetrate through the soils layers, due to the 

compactness of the soil. The non germinated seeds may also be those formed from the ray 

flowers that might be dormant at the time of sowing, and may germinate only after-ripening. Our 

results suggest that cultivating the soil to a minimum of 4 cm depth will reduce emergence of the 

weed seedlings and improve the management of H. subaxillaris. 

All herbicides applied pre- or post-emergence reduced the plant growth (seedlings fresh 

weight) more than 50%, except for oxyfluorfen which when applied post-emergence was inferior 

and reduced fresh weight by 32% only, but inhibited more than 50% of seed germination when 

applied pre-emergence (Fig 4, and 5 ). The mechanism by which the young weeds resisted the 

herbicide effect is not yet known. However, it could be due to poor retention and poor 

penetration of the herbicide applied post-emergence due to leaf surface (hairy) or texture 

(epicuticule thickness). Herbicide detoxification by unknown enzymes could be an option as 



280

well. In order to overcome this phenomenon, a surfactant and/or synergist should be added to the 

herbicide in order to increase the retention on and the penetration into the leaves. Oxyfluorfen 

may suppress seed germination and seedling growth when apply onto the soil prior to crop 

emergence since in this study, the pre-emergence treatment using oxyfluorfen controlled the 

weed. Different rates (g ai/ha) at which the various herbicides reduced 50% of the weed growth 

could be related to their different modes of actions. Sulfometuron at the rate of 1.5 g ai/ha 

reduced the weed growth by 50%, while diuron needs approximately 900 g ai/ha for such 

reduction (Table 1). The mixture of paraquat + diquat acts rapidly and reduced 90% of the fresh 

seedling weight within 3 DAT. However, the plant recovered and the weed control decreased to 

80% at 15, 18 and 21 DAT (Fig. 5). Since paraquat and diquat translocation is limited in the 

plant (described as contact herbicides by Mosier et al., 1990), the herbicide will be effective only 

when applied to immature weed leaf surface, and when the whole foliage is covered with the 

chemical in order to induce the necessary injury to the weed. 

Conclusions 

The ability of H. subaxillaris seeds to germinate in both light and dark conditions suggests 

that application of mulching materials will have less influence on the seed germination; however, 

dark will result in weak seedlings that might not develop into healthy plants. The germination of 

seeds in both cold and warm temperatures may explain the invasive nature of the weed and its 

wide spread and survival in different environmental conditions. Failure of ray seeds to germinate 

shortly after dispersal may increase the weed seed bank in the soil and seed longevity. Increased 

depth of sowing to a minimum of 4 cm will inhibit emergence of the weed seedlings. Cultivating 

the land prior to crop sowing will bury newly dispersed seeds deep into the soil, thereby 

inhibiting their emergence ability. Sulfometuron and diuron were effective in controlling seed 

germination and seedling growth when applied pre-emergence at 1.5 and 898 g ai/ha, 

respectively. Similarly, glyphosate, a mixture of paraquat + diquat, imazapyr, fluroxypyr, 

trifloxysufuron, and fomesafen, applied post emergence reduced weed growth by more than 

50%. 

In order to avoid/prevent recovery of treated weeds species, addition of adjuvant that might 

improve the retention on the leaf surface or/and increase the penetration into the leaf tissue might 

enhance the efficacy of the herbicides. 

Our experiments have shown that oxyfluorfen was effective when applied pre-emergence but 

cannot control the emerged weed seedlings. The mechanism for the weed resistance is not yet 

known, indicating the need for more research to understand the mechanism exploited by the 

weed to escape from oxyfluorfen effect and develop ways to manage it. 

References 

Awang MB & Monaco TJ (1978) Germination, growth, development, and control of Camphor weed (Heterotheca 

subaxillaris). Weed science 26, 51-57. 

Baskin JM & Baskin CC (1976) Germination dimorphism in H. subaxillaris var subaxillaris. Bulletin of the Torrey 

Botanical club 103, 201-206. 

Baskin JM & Baskin CC (1988) Germination ecophysiology of herbaceous plants species in a temperate region. 

American Journal of Botany 75,286-305. 

Datta SC, Evenari M & Gutterman Y (1970) The heteroblasty of Aegilops ovate L. Israel Journal of Botany 19, 463- 

483. 



281

Grin (2000) http://www.ars-grin.gov/npgs/tax/index.html (Accessed 25th May 2009). 

Harper JL (1965) Establishment, aggressiveness and cohabitation in weedy species. In: Genetics of Colonizing 

Species ed. Baker, H.G. & Stebbins, G.L. Academic Press New York. pp. 243-268. 

Hua C & Maun MA (1999) Effects of sand burial depth on seed germination and seedling emergence of Cirsium 

pitcheri. Plant Ecology 140, 53-60. 

Mosier DG, Peterson DE & Regehr DL (1990) Herbicide mode of action. P 1-11 

http://www.weedresearch.com/Articles/5059.PDF. (Accessed: 21st June 2009). 

Olsen KM (1997) Pollination effectiveness and pollinator importance on the population of H. subaxillaris. 

Oecologia 109, 114-121. 

Sung Y, Daniel JC, Russell TN & Warley MN (2008) Structural changes in lettuce seed during germination at high 

temperature, altered by genotype, seed maturation temperature and seed priming. Journal of American 

Society Horticultural Science 133, 300-311. 

Ungar IA (1971) Atriplex patula var. hastate seed dimorphism. Rhodora 73:548-551 

Weller, S.G. (1985) Establishment of Lithospermum caroliniense on sand dunes; the role of nutlet mass. Ecology 66, 

1893-1901. 

Yaacoby T (1998) The dispersion of the invasive weeds Hetherotheca subaxillaris and Verbesina encelioides in 

Israel. 6 th Mediterranean Symposium EWRS, Montpellier, France. 56-57. 

Zhang J & Maun MA (1994) Potential for seed formation in seven Great lake sand dune species. American 

Journal of Botany 81, 387-394. 



282

Mesquite (Prosopis juliflora): A threat to agriculture and pastoralism in Sudan 

Babiker, AGT -1 , Nagat EM -2 and Ahmed EAM -3 

1- College of Agricultural Studies, Sudan University of Science and Technology Khartoum Sudan. 

Sustech.edu, E-mail: agbabiker@yahoo.com 

2- Fedral Plant Protection Directorate Khartoum Sudan 

3- Agricultural Research Corporation, Sennar Research Station, Sennar, sudan 

Common mesquite [Prosopis juliflora (Swartz) DC] is a multipurpose ever 

green leguminous tree native to the Americas. The tree was introduced into 

Sudan in 1917 to combat desertification. Successful establishment and ability 

to fix sand dunes encouraged further introductions and deliberate distribution 

within the country. The tree was planted as shelterbelts around towns, cities 

and agricultural schemes in places threatened by desertification. 

Underutilization, mismanagement, over exploitation of natural vegetation, 

coupled with the invasive nature of the plant, enhanced rampant spread of 

mesquite and fostered colonization of variety of habitats. Currently the area 

under mesquite is estimated to be over one million hectares. The tree has 

become a national pest and is a threat to agriculture, biodiversity and 

pastoralism. The wide spread of mesquite in Sudan, the huge seed reserves in 

soil, the ability to regenerate from cut stump, coupled with high cost made 

eradication of mesquite an unlikely possibility. Management, which resides on 

containment, utilization and eradication of satellite foci seems to be the 

plausible solution. 

Prosopis spp. (mesquite) are multi-purpose ever green leguminous trees or shrubs. The genus 

comprises 44 species of which 40 are native to the Americas (Pasiecznik, 2001). Mesquite grows 

in arrays of environments and is not restricted by soil type, pH, salinity or fertility. In Sudan 

flowering is year-round (Babiker, 2006). The fruiting period, which peaks from December to 

June, coincides with the dry season. Mesquite leaves are unpalatable, while pods, renowned for 

their high sugar (16%) and protein (12%) contents are attractive to animals. The high degree of 

self incompatibility promotes hybridization and results in genetic variability, which as noted in 

similar situations, confers plasticity and allows colonization of a wide range of habitats (Hierro 

& Callaway, 2003). 

Common mesquite (P. juliflora Swartz, DC.), often multi-stemmed with a spreading crown of 

pendulous branches hanging down to the ground, is a copious seed producer (Babiker, 2006). 

The seeds, characterized by coat imposed dormancy, germinate in flushes and establish a huge 

persistent seed bank. Long distance transport of seeds is ensured by animals and water (Babiker, 

2006). 

Following germination mesquite seedlings grow vigorously (Ahmed, 2009). Tap roots reach 

deep water tables and extensive lateral roots spread well beyond the crown. The rapidly growing 

root system and un-palatability of foliage increase seedling survival rate and competitiveness 

particularly in heavy grazed areas and/or on uncultivated fallows. The high coppicing ability of 



283

mesquite ensures recovery of the plant when cut and often results in multistemmed trees. The 

trees have many competitive advantages over other plants however, the seedlings are somewhat 

sensitive (Pasiecznik, 2001). They colonize disturbed, eroded, overgrazed or drought-ridden land 

associated with unsustainable agronomic practices (Pasiecznik, 2001). The trees are believed to 

deplete groundwater reserves and to smother and suppress, through both allelopathic and 

competitive effects, growth of neighbouring plants (Ahmed, 2009). Prosopis pollens are said to 

be a major cause of allergic reactions and the thorns are poisonous and/or promotive to 

secondary infections on prickling (Takur & Sharma, 1985). 

Mesquite, at its centre of origin, the arid areas in South America, has played an important 

social role. In addition to its role in combating desertification and supply of high-value 

mechanical wood products, firewood and charcoal, mesquite provides shelters, animal feed and 

food for humans in areas where protein intake is very low and under adverse conditions of 

drought and famines (Ibrahim, 1989). The plant is important for fencing stalks, and as bee forage 

for honey production. Mesquite pods are a source of good quality flour and syrup which may be 

utilized in making foodstuffs at household levels (Pasiecznik, 2001; Felker et al., 2003). 

Mesquite species exude a water soluble gum that has been used as a substitute for gum Arabic 

during periods of restricted trading or international market shortages (Vilela & Ravtta, 2005). 

Mesquite species have ameliorating effects on soil under canopy. The tree fixes nitrogen and the 

leaf litter, when incorporated, improves soil physical and chemical properties. Leaves of 

mesquite are valued as compost (Pasiencznik, 2001). Foliage of mesquite contains several 

chemicals which are effective against several weeds; insects, fungi and some are of medical 

and/or industrial value (Pasiecznik, 1999). Moreover, mesquite, when properly managed, is a 

suitable tree for agroforestry in low-input low-rainfall areas (Luukkanen et al., 1983). 

Mesquite was introduced into several countries with the primary objective of curbing 

desertification and providing fire wood and thus preserving indigenous trees (Babiker, 2006, 

Chog & Chikamai, 2006). However, in most of the countries, where it was introduced, mesquite 

has spread outside where it was originally planted and has become a serious weed (ElHouri, 

1986). Ease of spread of mesquite is consistent with its invasive nature, ease of adaptations to 

novel environments, lack of natural enemies and underutilization and mismanagement (Ali & 

Labrada, 2006; Babiker, 2006; Kathiresan, 2006). It is noteworthy that exploitation of mesquite 

for wood and non-wood products in Sayun and Tarim in Yemen, in addition to the benefits 

realized by the community, curtailed spread of the tree and lessened its importance as a weed 

(Ali & labrada, 2006). 

P. juliflora, was introduced into Sudan in 1917 from South Africa and Egypt and planted in 

Khartoum (Broun & Massey, 1929). The success attained in establishment and the ability to 

tolerate drought, fix sand dunes and capacity to furnish shade, fuel, timber, fodder and edible 

pods provided the impetus for repeated introductions of the tree into various agroecosystems 

with emphasis on dry areas (Babiker, 2006). In the period 1978-1981 the tree was planted as 

shelterbelts on premises of major cities in eastern Sudan (Elsidig, et al., 1998). Moreover, 

introductions were made into various places in western and central Sudan. The tree was planted 

in shelterbelts around farms, irrigated schemes and along the Nile. Repeated introductions of 

mesquite from unknown sources (Pasiecznik, 2001), its deliberate distribution within the 

country, prevailing drought, livestock and feral animal‘s movement coupled with decreased land- 



284

use, land tenure, under utilization of the plant, mismanagement and over exploitation of natural 

vegetation have led to spread of mesquite into various locations where it has become a national 

pest (Elhouri, 1986). The plant constitutes a threat to agriculture, biodiversity and may lead to 

deterioration of natural vegetation and pastures and thus jeopardize the livelihood of a large 

proportion of the population, particularly, where livestock keeping and subsistent farming are the 

main avenues for income generation. 

The bulk of mesquite infestation (>90%) is in eastern Sudan, where livestock keeping and 

subsistence cultivation constitute the main source of income. Invading mesquite tends to form 

dense, impenetrable thickets. In pastures it reduces grass cover and stocking density, interferes 

with mustering of stalk and threatens the livelihood of traditional pastoralists. Invasion into 

agricultural land, along irrigation channels and water courses is also a major problem. (Elsidig et 

al., 1998). 

In Sudan as in most of the countries, where mesquite has been introduced, it is underutilized. 

Its use, beside sand dune fixation is limited to fuel wood and charcoal production (Babiker, 

2006). Animal rearing constitutes the main livelihood of landless and resource poor farmers in 

many of the mesquite endemic areas. Unpalatability of P. juliflora leaves to livestock limits their 

use as animal feed. Results from trials on feeding mesquite pods to sheep were also 

disappointing and over 90% of livestock owners in eastern Sudan regard mesquite as a liability 

(Elsidig et, al., 1998). 

Several efforts were made in Sudan to eradicate mesquite (Babiker, 2006). However, because 

of high cost and complexity of the problem, most of the efforts were not successful or 

sustainable. In 1995 the government approved a bill on mesquite management. The tree is to be 

eradicated where it constitutes a threat to agriculture or biodiversity and preserved in areas 

threatened by desertification. Active eradication programmes, using both mechanical and manual 

methods for uprooting mesquite, were implemented in various locations in the country, at very 

high cost, and with variable results (Babiker, 2006). Soil disturbance resulting from uprooting 

brings mesquite seeds to the surface soil and aids its regeneration (Ahmed, 2009) 

Global experience showed clearly that eradication of mesquite is neither desirable nor tenable 

(Pasiecznik, 1999). Mesquite, if properly managed, through containment, utilization and 

eradication of satellite foci, could be a boon to the rural poor. Mesquite, in addition to 

curtailment of sand dunes, provides several wood and non-wood products which could be of 

benefits to rural communities in dry areas where no other trees could grow and flourish. 

However, when not properly managed mesquite proved to be a serious invasive weed. Peattie 

(1953) concluded that mesquite is an elemental force comparable to fire too valuable to 

extinguish completely and too dangerous to trust unwatched. 

Mesquite seeds are the main vehicle for long distance transport. Satellite foci are pivotal for 

establishment of colonies (Babiker, 2006). Mesquite, as is the case with many invasive alien 

plants, spreads by seed dispersal and repeated establishment of satellite foci from a founder 

population (Moody & Mack, 1988). Environments with open niches, abandoned land or overgrazed 

and drought stricken sites are the most vulnerable to invasion. Mesquite, upstream, on 

rivers, water courses and irrigation canals or in premises of irrigated schemes displays a high 



285

tendency to spread. The huge seed bank and basal buds endow mesquite with a high capacity for 

regeneration after cutting and/or uprooting. Efforts have to focus on containment and maximum 

utilization. To curtail mesquite invasion seed movement should be discouraged or the seeds 

should be devitalized, satellite foci should be denied establishment, over exploitation of natural 

vegetation and overgrazing of marginal land should be discouraged. Land tenure in mesquite 

endemic areas should be reviewed. Satellite foci and mesquite infestations on strategic and high 

risk areas such as irrigation canals, water courses and agricultural land should be eradicated. 

Ways and means for utilization of the removed mass should be designed to generate income for 

farmers and pastoralist. Following destruction mesquite has to be replaced by appropriate trees 

and/or crops. The treated area has to be vigilantly observed and interventions by chemical and/or 

mechanical mean should be implemented to discourage regeneration. 

Mesquite when not a threat to agricultural lands or biodiversity and in areas prone to 

desertification should be conserved and ways and means for its management and utilization 

should be developed. 

At present a research programme with the prime objective of developing sustainable and 

economically viable management site specific strategies which offer several options have been 

proposed. The strategies, based on containment and utilization, are to take into account 

distribution of mesquite, infested areas, their possible contribution to further spread of the plant, 

socio-economic aspects of mesquite, its environmental impact, indigenous methods of 

management and utilization and their possible improvement through research generated 

technologies. 

References 

Ahmed EA (2009) Studies on Some Aspects of Mesquite Biology and Management. Ph.D Thesis Sudan Academy of 

Sciences. PP 162 

Ali A & Labrada R (2006) Problems posed by Prosopis in Yemen. In: Labrada R (ed.) Problems Posed by the 

Introduction of Prosopis spp. in Selected Countries. Plant Production and Protection Division, Food and 

Agricultural Organization of the United Nations Rome, pp 21-28 

Babiker AG (2006) Mesquite (Prosopis spp.) in Sudan: history, distribution and control. In: Labrada R (ed.) 

Problems Posed by the Introduction of Prosopis spp. in Selected Countries. Plant Production and Protection 

Division, Food and Agricultural Organization of the United Nations Rome, pp 11-20 

Broun AF & Massey RE (1929) Flora of the Sudan: Thomas Murby and CO., p 376 

Chog SK & Chikamai BN (2003) Experiences of Prosopis utilization and management from outside Kenya. In: 

Proceedings of the Workshop on Integrated Management of Prosopis Species in Kenya (Choge, S. K. and 

Chikamai, B. N. eds.) pp 78-92. Kenya Forest Research Institute (KEFRI) 

El Houri AA (1986) Some aspects of dry land afforestation in the Sudan, with special reference to Acacia tortilis 

(Frosk) hayne, Acacia seyal Willd. and Prosopis chilensis (Molina) Stunz. Forest Ecology and Management 

16, 209-221. 

Elsidig NA, Abdelsalam AH & Abdelmagid TD (1998) Socio-Economic, Environmental and Management Aspects 

of Mesquite in Kassala State (Sudan) Sudanese Social Forestry Society. pp 96. 

Felker P, Grados N, Cruz G & Prokopiuk D (2003) Economic assessment of flour from Prosopis alba and P. pallida 

pods for human food applications. Journal of Arid Environment 53, 517-528 

Hierro JL & Callaway RM (2003) Allelopathy and exotic plant invasion. Plant and Soil 256, 29-39 

Ibrahim KM (1989) Prosopis species in the South-western United States, their utilization and research. In: Dutton 

RW, Powell M, Ridley RJ (edits) Prosopis Species Aspects of their Value, Research and Development. 

Proceedings of the Prosopis Symposium. Cord, University of Durham, pp. 83-115 

Kathiresan RM (2006) Invasion of Prosopis juliflora in India. In: Labrada R (ed.) Problems Posed by the 

Introduction of Prosopis spp. in Selected Countries. Plant Production and Protection Division, Food and 

Agricultural Organization of the United Nations Rome, pp 3-10 



286

Luukkanen O, Turakka & Holmberg G (1983) Forest nursery and afforestation experiments in the White Nile and 

north Kordofan provinces in Sudan. Sudan-Finland Consulting Programme in Forestry Technical Report 7, 

pp.25 

Moody ME & Mack RN (1988) Cotrolling the spread of plant invasions: The importance of nascent foci. Journal of 

Applied Ecology 25, 1009-1021 

Pasiecznik NM (2001)The Prosopis juliflora- Prosopis pallida Copmlex: A Monograph. HDRA the Organic 

Organization. Pp 162 

Peattie DC (1953) Natural History of Western Trees. Riverside Press, Cambridge, Boston, USA (Cited Pasiecznik, 

1999) 

Takur IS & Sharma JD (1985) Isolation and characterization of allergens of Prosopis juliflora pollen grains. 

Biochemistry Intenational 11, 903-912. 

Vilela AE & Ravetta DA (2005) Gum exudation in South-American species of Prosopis L. (Mimosaceae) Journal of 

Arid Environment 60, 389-395 



287

Is bio control of Ambrosia spp. with Epiblema strenuana found in Israel possible? 

Tuvia Yaacoby 

Plant Protection and Inspection Services, P. O. Box 78 Bet Dagan 50250 Israel. 

E-mail: tobyy@moag.gov.il 

Several new species of Ambrosia were found in Israel during the last years. Ambrosia maritima 

L. is the only species of this genus present in the Israeli flora. A. trifida and A. artemisifolia were 

found in the Northern Galilee in a feeding birds (Cranes) migration field with corn grains 

imported from the USA. Another species of Ambrosia was found in the central regions of the 

country. A. confertiflora was found in the Heffer valley area along the Alexander river banks 

spreading in a nature reserve area, sub-tropic orchards and affecting farmers‘ incomes and 

biodiversity. An update survey carried out in summer 2007 indicates that this species was 

introduced to Heffer valley from Nablus (Palestine authority) via sewage and rainfall water 

which ran downhill towards the Alexander River. More recently we found other populations of 

the weed far away from the initial growing areas probably introduced by agri-machinary or 

transfer of soils. Another species, A. tenuifolia was found North-West of the Heffer valley 

exhibit supreme adaptation to the places invaded. Like A. confertiflora this weed produces 

underground rhizomes and seeds. Both, A. confertiflora and A. tenuifolia are hard to kill, 

perennial noxious weeds and extreme rates of non selective herbicides like 2,4-D, fluroxypyr and 

glyphosate are needed to manage them. During a survey carried out in summer 2008 a few larvae 

of the stem galling moth were found in the small population of A. tenuifolia indicating that this 

moth was introduced to Israel sometime earlier. A survey carried out in summer 2009 reveals the 

"good" news of finding this moth on A. confertiflora plants too. The Australian experience using 

such bio control agent against these types of invasive weeds will serve the Israeli P.P.I.S 

authorities as a base for starting a program using Epiblema strenuana as bio control agent. 



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Lists of invasive alien plants as a key issue/tool for effective management 

Pavol Eliáš 

Dept. of Ecology, Slovak Agricultural University, Marianska 10, Sk – 949 76 Nitra, Slovakia, 

E-mail: pavol.elias@uniag.sk 

Introduction 

Lists of invasive alien species (IAS) are considered as a key issue and tool 

for the effective management of the invasive non-native species in a region 

(a country). These lists are generally composed of the non-native (alien) 

species that exhibit an invasive behaviour in a region. These lists 

predominantly indicate the invasive status and/or the environmental impacts 

of the listed species. They provide information on/identify the species which 

represent highest priorities action, including quarantine measures. It means 

they highlight problem species and focus attention on non-native species 

considered to be a risk for native biodiversity and environment. Lists are 

used for early warning, monitoring, eradication and control, education and 

communication at local, regional and global scales. The author analysed and 

compared existing current lists of invasive alien plants (IAPs) across the 

world and distinguished four types of IAPs lists which differ in species. 

They are: (i) worst invasive species lists (top ―ten‖, dirty, ―the most 

invasive‖, ―the most important‖ species etc.), (ii) global, regional, national, 

local lists of invasive species, (iii) quarantine pests lists (black, white, 

watch, alert=alarm lists, etc.), and (iv) annexes of national and international 

specific legislation (used as official documents for management activities in 

a country/region/globe). 

Important differences in number of listed species found can be caused by 

differences in the definitions (concepts) and criteria used for the 

identification and categorisation of the invasive non-native species, by 

different levels of knowledge about the status and distribution of non-native 

species, methods of list preparation and subjectivity of experts‘ opinion. In 

this task the lists have to be based on continuous field research of invasive 

behaviour of the alien species and not only on simple inventories and/or 

compilation of current floristic/faunistic data. Scientific make researches on 

the invasive behaviour of non-native species and on invasion processes are 

needed to collect data for quantitative criteria of invasiveness and for better 

understanding of the ecological process. The lists have to be up-to-dated in 

a 5 to 10 year periods by re-assessment of non-native species due to high 

dynamics of the process of invasions and changes in landscape. 

The lists are also important tool for communication with policy makers, 

planners, managers of natural resources, stakeholders, land owners, the 

public, increasing their interest in invasive non-native species management, 

providing the up-dated information on invasive non-native species. 

The effective management of alien (non-native) plants in a region (or in a country) is 

firstly dependent on the identification of those plant species which have the highest priority 

for actions. To this purpose the species are usually listed in the lists of invasive species. 

The lists consist of the non-native (alien) species that exhibit invasive behaviour in new 

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environment (region), rapidly increasing the area occupied (spread), establish local 

populations and form metapopulations in new environments, penetrate into semi-natural 

and natural communities (habitats), forming mono-dominant dense stands and suppressing 

native species (Eliáš, 1997; 2009) (Table 1). 

Table 1 Characteristics of invasive behaviour of alien (non-native) species in a region 

(Eliáš, 2005; 2009) 

Invasive behaviour of non-native species: 

(i) rapid increasing of distribution in the occupied area (spread), 

(iia) establishment of new local populations in the region and 

(iib) formation of metapopulations in new environment (colonization), 

(iii) penetration into semi-natural and natural communities (habitats) in new region (invasion 

sensu stricto), 

(iiib) formation mono-dominant dense stands in occupied sites (habitats), and 

(iv) suppression of native species in the recipient region. 

Lists of invasive alien species (IAS) are important tools for management of non-native 

organisms from different aspects. They predominantly: 

(a) highlight problem species and focus attention on non-native species 

considered to be a risk for native biodiversity and environment. 

(b) indicate invasive status and/or environmental impacts of listed species, 

(c) provide information on/identify the highest priority IAS which need 

action, including quarantine measures, as well as 

(d) provide guidance to environmental managers and raise public 

awareness on the impacts of the most harmful invaders. 

The first step in tackling IAS consists in identifying those species that can behave 

invasively and, therefore, could represent a potential threat to managed and unmanaged 

habitats. Identifying future invaders and predicting their likely sites of invasion are of 

immense scientific and practical interest (Mack et al., 2000). In practical terms, it could reveal 

the most effective means to prevent future invasions. 

The sixth aim of the European Strategy on Invasive Alien Species involves early detection 

and rapid response (Genovesi & Shine, 2004). It recommends that parties have 

comprehensive and cost-effective surveillance procedures in place. 

The European and Mediterranean Plant Protection Organization (EPPO) reviews and 

organizes data on alien plants in order to build an early warning system. It developed a 

prioritization system to select species that represent emerging threats and require the most 

urgent pest risk analysis to implement preventive measures and to perform eradication and 

management measures (Brunel et al., 2010). One of EPPO‘s tasks is therefore to draw up lists 

of pests that present a phytosanitary risk, and which regulation is relevant for the whole of, or 

parts of, the EPPO region, composed of 50 European and Mediterranean countries. 

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Material and methods 

Current lists, catalogues as well as databases of non-native plant species published and/or 

presented in the literature and in documents on invasive alien species and their management 

in Europe and other continents (cf. Sellers et al., 2010) were collected and analysed (Table 2). 

The lists were compared by set of species, priorities, 

The lists of IAPs in six neighbouring Central-European countries – Austria, Czech 

republic, Poland, Slovakia, Hungary and Slovenia (Fig. 1) were compared by set of listed 

species and differences in number of species were identified. 

Table 2. Lists of IAS as tool for effective management on global, regional, national and 

local levels (Eliáš 2000; 2009, addition) 

Level Management Priorities Invasive Alien Lists and 

1. Global International Cooperation 

global level 

2. Regional Prevention – regional 

quarantine 

3. National 

4. Local 

databases 

100 of the World´s Worst 

Invasive Alien Species 

(IUCN/ISSG) 

Global Early Warning System Global Invasive Alien Species 

Database (GISD) 

Migration path control 

Invasion process research on 

The worst invasive alien species 

threatening biological diversity 

in Europe (EEA 2007) 

Regional early warning and One hundred of the most 

rapid response system 

invasive alien species in Europe 

Monitoring and early detection DAISIE database 

Risk assessment EPPO Alert list and database 

Spread reduction NOBANIS database 

Metapopulation size regulations 

Integrated ecosystem 

management 

Landscape management 

Biotic invasion research 

Education, training 

Prevention – Quarantine on 

national level 

Country lists, catalogues and 

databases 

Public education Non-native (alien) species lists 

Environmental managers 

training 

Ecosystem protection 

Eradication 

Regulation of local population 

size 

Restoration of habitats and 

ecosystems 

Administrative unit/District lists 

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To demonstrate the legislation process delay the list of the most important invasive species 

in Slovakia (Eliáš, 1998; 2001) was compared with list in Annex of the Act No. 24/2003 

Ministry of Environment of the Slovak Republic and EPPO Alert list – terrestrial plants only 

(Table 6). 

Results and discussion 

Types of invasive alien species lists 

Our survey and analysis of the lists of invasive alien plants have shown that we can 

distinguish four different types of IAPs lists. 

(1) Lists of worst invasive species whith limited numbers of species, selected to 

prioritizing methods based on their invasiveness and/or impacts. These lists are usually 

published as ―top ten‖, ―dirty‖ ―the most invasive‖, ―the most important‖ etc. alien species. 

(2) Lists related to geographical boundaries such as global, regional, national, local lists of 

invasive species. They indicate the alien species that exhibit invasive behaviour in the 

considered scale/level, e.g. in a continent (Europe), a country (Turkey) or a microregion 

(locality). In the context several alien lists, catalogues and databases of this type have been 

published and/or prepared as tools for the effective management (Table 2). 

(3) Quarantine pests lists (black, white, watch, alert=alarm, etc.) which have been used as 

a tool within quarantine measures to stop the introduction of highly invasive non-native 

species (with a high invasive potential), ranked as invasive in other countries, or simply listed 

in national lists of neighbouring countries. 

(4) Official lists published in the framwork of national and international legislation in force 

or in their annexes. The non-native species listed by the regulations are usually declared by 

Acts and/or Directives/Conventions and are used as official documents for management 

activities in a country/region/globe. 

The worst invasive species 

The first type of the lists, the worst invasive species lists are prepared as a global list 

(GISD-Global Invasive Species Database), continental lists (e.g. Europe, Worst invasive 

alien species threatening biodiversity in Europe, EAS/SEBI 2010, EEA 2007), and many 

different national lists (e.g. Slovakia by Eliáš, 1997, 1998, 2001, Germany by Scherer- 

Lorenzen et al., 2005, etc.), microregional lists etc. 

The global list of the International Union for the Conservation of Nature (IUCN) called 

"One Hundred of the World’s Worst Invasive Alien Species", is a part of the Global 

Invasive Species Database (GISD). It lists invasive species which have been recognised 

globally as a major threat to biodiversity (the collected wealth of the world´s species of plants, 

animals and other organisms) as well as to agriculture and other human interests. These 

species were selected for the list according to two criteria: their serious impact on biological 

diversity and/or human activities, and their illustration of important issues surrounding 

biological invasion. To ensure the inclusion of a wide variety of examples, only one species 

from each genus was selected. Absence from the list does not imply that a species poses a 

lesser threat (Love et al., 2000). 

The European Environmental Agency (EEA) has produced, within the SEBI 2010 project, 

a list of the worst invasive alien species threatening biological diversity in Europe (EEA 

2007). This list contributes to the general indicator of changes in biological diversity caused 

by invasive alien species. The list identifies species that should be a priority for more detailed 

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monitoring, research and management (EEA 2007). Another list produced by the DAISIE 

research project listed ‗One hundred of the most invasive alien species in Europe‘ (Vilà et al., 

2009). The criteria used were different, predominantly a serious impact on biological diversity 

(e.g. for the European list: severe impacts on ecosystem structure and function; replacement 

of a native species throughout a significant proportion of its range; hybridisation with native 

species; threats to unique biodiversity (e.g. endemic species). And also negative consequences 

for human activities, health and/or economic interests (e.g. is a pest, or a vector of disease). 

Regional lists of most invasive alien were prepared for the North European and Baltic 

region (Gollasch et al., 1999; NOBANIS 2007) and also for the Mediterranean Sea (CIESM 

2007). EPPO also drafted in the earlier stages of its work a list highlighting the most invasive 

alien plants in the EPPO region (the EPPO List of Invasive Alien Plants). This list aims to 

draw attention to those species whose entry into EPPO countries should be prevented, or 

should be submitted to control measures to prevent further spread (Brunel et al., 2010). 

These types of lists of the most prominent alien invaders are considered as one of the 

primary tools for raising awareness on biological invasions (Vilà et al., 2009). 

Quarantine pests 

Quarantine pest lists identify those alien species that may become invasive and therefore 

require special attention (McNeely et al., 2001). Effort to prevent the opportunity for 

invasions by prohibiting the entry of the non-native species into new range is required (Mack 

et al., 2000). Quarantine pests are pests of potential economic importance to the area 

endangered thereby and not yet present there, or present but not widely distributed and being 

officially controlled (IPPC 2005). 

The identification of the quarantine pest themselves - e.g. at customs, may be an important 

first step in preventing the introduction of non-native species in new areas. The International 

Plant Protection Convention (IPPC) developed international standards for phytosanitary 

measures at the global, regional and national levels (IPPC 2005). 

Listing of the species is one effective tool for dealing with IAS issues (Wittenberg et al., 

2001; Shine et al., 2000, Mooney et al., 2005). Global Strategy on Invasive Aliens Species 

(GSIAS) distinguished three different types of quarantine lists: 

• Black lists: list of invasive alien plants that currently cause damage in the areas of 

biodiversity, health, and/or economy. The establishment and the spread of these species must 

be prevented. The species listed are known to be invasive and so harmful that their 

introduction should be prohibited under national legislation. 

• White lists: species known on the basis of stringent criteria to have such a low 

probability of invasion that they can be introduced. The species through passing a risk 

assessment analysis can reasonably be declared as safe (put on a "white list"), though 

monitoring is still required to ensure that the prediction remains accurate over time. 

• Grey lists: listed species whose probability of becoming invasive is unknown. The 

potential invasiveness of the majority of the world's species is unknown and they should be 

placed on a "grey list" (Wittenberg et al., 2001). 

The European Strategy on Invasive Alien Species (Genovesi & Shine, 2004) has used the 

same categories as possible components of an agreed listing system for alien species in 

Europe: Black list, White list, and Grey (holding) list. This approach have been 

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implemented also by the Council of Europe in a document entitled ―Towards a black list of 

invasive alien species entering Europe through trade, and proposed responses‖ (Genovesi & 

Scalera 2007), which led to Recommendation No. 125 (2007) of the Standing Committee, 

adopted on 29 November 2007, on trade in invasive and potentially invasive alien species in 

Europe. 

In quarantine measures a watch list is also recognised – this is a list of invasive alien 

plants which have the potential to cause damage. Their spread needs to be monitored and if 

necessary prevented. The species already cause damage in neighbouring countries. 

Brunel et al. (2010) identified, on the basis of surveys and rapid assessments of spread and 

impact, emerging invasive alien plants for Mediterranean countries These species represent 

priorities for action. Some other species were placed on the observation list, due to lack of 

information (available information does not allow them to be counted among the worst 

threats). 

The EPPO Alert List, part of the pest warning system managed by the EPPO Secretariat 

and information on pests, listed in the Alert List is published in the EPPO Reporting Service 

(see EPPO Website, 2010). It is not a quarantine list, and does not constitute a 

recommendation for phytosanitary action. 

The Early warning and information system for invasive alien species (IAS) threatening 

biodiversity in Europe (EEA 2010) suggested the development of an Early warning and 

rapid response system (EWRR): a framework designed to respond to biological invasions 

through a coordinated system of surveillance and monitoring activities; diagnosis of invading 

species; assessment of risks; circulation of information, including reporting to competent 

authorities; and identification and enforcement of appropriate responses. The identification of 

alien species that are already or are likely to become invasive is central to prevention and 

rapid, targeted action to combat invasive species within Europe. An effective response relies 

on being able to pinpoint those species currently absent from Europe but likely to enter at 

some future time, as well as species that are already present but that have not yet become 

invasive and/or widespread. Species can be assigned to the following three broad categories: 

Alert lists (alarm list): list of alien species not yet present in a territory or present only in 

a very limited range that pose risks to the invaded area, and for which it is recommended to 

apply particular surveillance and monitoring efforts in order to enhance prompt response in 

the case of arrival/expansion. 

Black list: a list of alien species that have been shown through risk assessment to pose 

risks to the environment, economy or human well being. 

Watch list: a list of alien species not yet present in a territory - or present only in a limited 

range - that are considered potentially to pose risks to the invaded area and for which it is 

recommended to monitor arrival, expansion and impacts, and/or application of prevention 

measures. 

Differences between the lists 

The above four types of IAPs lists differ in species listed because of their aims, goals, 

application and role in the management of non-native species. The second (and to some extent 

the first) type of lists are based on scientific data resulting from field research of invasive 

behaviour of non-native species in a region. The third and fourth types are based on surveys 

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and/or compilations of published data and are included into early warning systems for 

quarantine invasive species. 

Figure 1 - Numbers of invasive alien plant species in six Central European countries 

published in official national lists. Numbers in parenthesis indicate invasive + potential 

invasive alien plants (Eliáš 2008). 

It should also be noted that the lists of the same type can be different in the same region. 

The comparison of lists of IAPs in neighbouring Central-European countries (Fig. 1) has 

shown large differences in number of listed species (from 27 to 79). It was concluded that the 

differences can be caused not by ecological and socio-economic conditions in the countries 

(they are very similar) but predominantly due to/by differences in definitions (? concepts) of 

invasive alien species and criteria used for identification and categorisation of the invasive 

non-native species (Eliáš, 2006; 2008). 

Table 3. Comparison of different approaches to definitions of terms ‗invasion‘ and 

‗invasive species‘ (Eliáš, 1997; 2009). 

Approach Priority Process Terms used 

1. Biogeographical Origin of species Introduction and 

expansion out of 

2. Ecological Behaviour of local 

population(s) of a 

species 

3.Anthropocentric 

and environmental 

Impact, effect, 

consequence 

original range 

(massive/sudden?) 

penetration, entry 

into a community 

(biocoenosis) and 

ecosystem 

Economic and 

ecological losses, 

changes in structure 

and diversity, 

biodiversity threats 

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Alien, Imported, 

Exotic, Introduced, 

Non-native 

Invasive species 

Invading species 

Colonist, Colonizer 

species 

weed, pest, 

environmental 

weed 

(„invader―), 

problem species, 

biological pollutant, 

transformer species 

296

The term ―invasive‖ has no standard definition (Shine et al., 2000). It is interpreted in 

varying ways (cf. Eliáš 1997; 2009; Richardson et al., 2000, Table 3) and sometimes used 

interchangeably with well-established terms such as ―pest‖ or ―weed‖ that can apply to native 

as well as alien species (Table 4). 

Table 4 Differences between weeds and invasive plants in origin (evolution), condition 

(habitat, environment) and impacts (Eliáš, 2005) 

Characteristics (Agricultural) Weed Invasive alien plant 

Origin (evolution) unwanted plants in cultivated 

areas, adopted to frequent 

anthropogenic disturbances 

Environmental condition 

(habitat, environment) 

Arable fields, cultivated sites, 

agroecosystems 

Impacts Economic losses, they can 

compete with cultural plants 

for resources such as space, 

nutrients, water etc. reduced 

their growth and production 

introduced plants which 

have become naturalized and 

have invaded natural 

ecosystems 

invaded native ecosystems, 

disturbed sites in native 

habitats 

adversely affect the survival 

of indigenous flora and 

fauna, can compete with 

indigenous plants for 

resources such as space, 

nutrients 

Serious negative impacts on native biodiversity and/or economic losses as criteria of 

invasiveness are also subject of scientific discussion. Richardson et al. (2000) suggested that 

―invasive‖ should be used with reference to their ―biogeographic/demographic‖ status of 

a species without any connotation of impact. 

Different levels of knowledge about the status and distribution of non-native species, ways 

of list preparation and subjectivity of experts opinion can also caused the differences in the 

IAPs lists. In this task, therefore, the lists have to be based on continuous field research of 

invasive behaviour of the aliens and not only on simple inventories and/or compilation of 

current floristic/faunistic data. The list of the 100 most invasive alien species in Europe 

species is based on expert opinions: species were nominated to the list by experts working 

within the DAISIE research project. They are perhaps better considered as representatives of 

all main taxonomic groups and all environments and were selected to represent diverse 

impacts on ecology, socio-economic values and human and animal health (cf. Vila et al., 

2009). Until now such compilations have been available only for few countries. 

Organisms in the EPPO Alert list are selected by the EPPO Secretariat (based on literature 

review, new occurrences, new records of invasiveness) or are proposed by National Plant 

Protection Organisations. The section 'possible risk' is not the result of a full PRA according 

to EPPO Standard PM 5/3(1) but is a preliminary attempt by the EPPO Secretariat to identify 

the main elements of risk. The addition of pests to the list is marked by an article in the EPPO 

Reporting Service. All pests on the Alert List are selected because they may present a 

phytosanitary risk for the EPPO region. There are various reasons for considering inclusion 

on the Alert List: pests which are new to science, new outbreaks, reports of spread, etc. The 

Alert List is reviewed critically every year by the Panel on Phytosanitary Measures (EPPO 

Website, 2010). 

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Different lists of species considered invasive by different experts from many countries in 

the Mediterranean area were collected; they have been shared with all participants of the 

workshop and interested experts, but have never been published. 

Invasive status categories 

Non-native species differ in their invasive behaviour in new regions and these differences 

have to be indicated by invasive status category. For assessment of invasive behaviour of 

aliens we need more invasive categories to indicate different invasive status of non-native 

species in a region. 

The following invasive status categories have been distinguished: not-established (casual), 

established and/or escaped, naturalized, potential invasive, local invasive, regional invasive, 

transformer, and post–invasive species. 

Not-established (casual) is alien plant that may flourish and even reproduce occasionally 

in an area, but which do not form self-replacing populations. 

Established and/or escaped, 

Naturalized plants are alien plants that reproduce consistently and sustain populations 

over many life cycles without direct intervention by human. 

Potential invasive 

Local invasive, 

Regional invasive plant 

Transformers are those species (taxa) that have evident impacts on ecosystems. Those 

alien species, invasive plants which change the character, condition, form or nature of 

ecosystem over a substantial area relative to the extent of that ecosystem (Wells et al., 1986, 

Richardson et al., 2000). 

Post–invasive species 

The categorisation process is based on data from field research in the region. We need 

quantitative criteria to assess of invasive status of non-native species in a region. The criteria 

for quantitative assessment of invasive status of non-native species in a region are shown in 

Table 5. 

Table 5. Criteria for quantitative assessment of invasive status of non-native species in a 

region 

Quantitative criteria for assessing invasiveness 

(1) Reproduction and dispersal (production of large amount of offspring in short period). 

(2) Spread (expansion) rate (increasing number of localities and/or area occupied). 

(3) Establishment of local populations and formation of metapopulation (increasing number of 

local populations and number of occupied habitats by metapopulations in a region). 

(4) Environmental negative impacts (identification of hazards, damage to native species, 

communities and ecosystems). 

Quantitative criteria of invasiveness of non-native species are dependent, as shown above, 

on science-based data. Scientific research of invasive behavior of non-native species and 

invasion process are needed (i) to collect data for evaluation/assessment of invasion status of 

non-native species by quantitative criteria of invasiveness and (ii) to understand the ecological 

process better. 

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The first three criteria (Tab. 5) indicate an ability of an alien species to establish and spread 

in a region (geographical distribution). The fourth criterion indicates ecological, 

environmental and socio-economic impacts of invasive behaviour of non-native species in 

a region. It is related to the third criterion related to forming of dense stands in occupied 

(colonized) habitats. 

Risk assessment 

Impacts of invasive behaviour of non-native species in a region can be predicted by risk 

assessment (RA) procedure. It can evaluate (i) high probability of establishment, expanding 

and causing damage, (ii) invasive behaviour risk (species that could become invasive) as well 

as (iii) negative impact risk (environmental, economic, health-related, ?political). 

The risk assessment process is commonly used to rate and rank known or suspected 

invasive species. The objectives are a prediction of whether or not a species is likely to be 

invasive and relative ranking of risk (Wittenberg et al., 2001). 

Since 2006, EPPO has been engaged in the drafting of a method for prioritizing alien 

plants, based on relatively simple but robust criteria. As performing full Pest Risk Analysis 

(PRA) for all the invasive alien plants already present within the EPPO region would require a 

vast input of resources, the general philosophy of the prioritizing process is to select those 

species for which a PRA constitutes an adequate tool (Brunel et al., 2010). 

Ranking of relative risk have been assess by a simple qualitative or semi-quantitative 

rating of three scores: ―high‖,―medium‖ and ―low‖. Also in the RA procedure to assess the 

risk precise quantitative criteria and data based on scientific research and monitoring is 

needed. In Canada, for organisms of forestry concern, the Canadian Food Inspection Agency 

and the Canadian Forest Service work closely to develop science-based policies and 

regulations (Allen & Cree, 2005). 

The maintenance of the lists 

Invasion of non-native species is a dynamic process. Changes in geographical distribution 

of species, number of localities and metapopulations as well as impacts. Invasiveness of alien 

species can vary with tine, genetic composition of the introduced population, and changes in 

human behaviour. The lists (white lists, watch lists, etc), therefore, have to be re-assessed in 

appropriate intervals (cf. also Wittenberg et al., 2001). The lists could be kept up to date in 5 

to

Legislation to support management of IAS 

Legal frameworks are essential to support efforts to manage IAS, working at both national 

and international levels. Global Invasive Species Programme (GISP) has produced a Guide 

for Designing Legal and Institutional frameworks on IAS (Shine et al., 2000), seeking to 

provide an essential tool in this regard. Any legal framework at the national level needs to 

include adequate provisions for mitigating the impacts of IAS, a challenge that faces 

numerous constraints (e.g. lack of resources). 

Table 6. Comparison of list of the most important invasive species in Slovakia (Eliáš 1998, 

2001) with list in Annex of the Act No. 24/2003 Ministry of Environment of the Slovak 

Republic and EPPO Alert list – terrestrial plants only 

Invasive plants of Slovakia Annex species EPPO Alert list – terrestrial 

plants only 

Acer negundo (= Negundo 

aceroides) 

Abutilon theophrasti 

Acer negundo 

Acroptilon repens 

Ailanthus altissima Ailanthus altissima 

Ambrosia artemisiifolia 

Amelanchier spicata 

Aster novi-belgii agg., Aster 

lanceolata 

Bidens frondosa 

Bunias orientalis 

Cenchrus incertus 

Cyperus esculentus 

Echinocystis lobata 

Fallopia japonica, F. 

sachalinensis, F. x bohemica 





Galinsoga ciliata, G. parviflora 

Helianthus tuberosus Helianthus tuberosus 

Heracleum mantegazzianum Heracleum mantegazzianum Heracleum mantegazzianum 

Heracleum sosnowskyi 

Impatiens glandulifera Impatiens glandulifera Impatiens glandulifera 

Impatiens parviflora Impatiens parviflora 

Licium barbatum 

Lupinus polyphyllus Lupinus polyphyllus 

Panicum spp. 

Prunus serotina 

Rhododendron ponticum 


Rudbeckia laciniata 

Senecio inaequidens 

Solidago canadensis, S. 

gigantea 

Solidago canadensis, S. 

gigantea 

Solanum elaeagnifolium 

Solidago canadensis, S. gigantea 

Sorghum halepense 

Spartina anglica 

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The legislation process have to be followed the lists re-assessment and actualisations and 

annexes, therefore, have to be updated. The delay in the legislation process can support spread 

of many invasive non-native species in new regions due to limit financial sources for 

eradication, more intensive monitoring, early warning and control, as well as other 

instruments used in environmental management. In Slovakia, for example, more than 20 

invasive species are listed in the national list of the most important invasive plants (Eliáš 

2001) but the Act of 2003 listed only 7 invasive alien plants (Table 6). 

It was mentioned that the "invasive" classification is quite separate from jurisdictional or 

administrative boundaries. If an alien species is invasive, it is unlikely to stay within the 

boundaries of the ecosystem, municipality or region to which it was introduced. One 

consequence for legal systems is that site specific restrictions (for example, a prohibition on 

introducing alien species into protected areas) can never be more than a partial strategy for 

preventing or mitigating impacts of invasions. Thus, regional collaboration between countries 

in regard to IAS is essential. Numerous legal principles, approaches, and tools have been 

developed for dealing with problems of IAS (Shine et al., 2000). 

Tool for communication 

The IAS lists are an important tool for communication with policy makers, planners, 

managers of natural resources, stakeholders, land owners, the public, and others involved in 

invasive species issues. They increase interest in invasive non-native species management and 

provide updated information on invasive non-native species (Eliáš 2009). Good experience 

and the importance of the role of the tools has been shown by the IUCN‘s 100 of the World‘s 

Worst Invasive Species list (Love et al., 2000) which has been very influential in raising 

awareness and supporting the development of policy conservation instruments relevant to 

biological invasions (Shine et al., 2000). The DAISIE accounts of the 100 of the most 

invasive species may play a major role in raising public awareness and supporting the 

activities of a broad spectrum of professionals including land-use and wildlife managers, 

environmental policymakers, environmental educators, journalists, students and other 

stakeholders (Vilà et al., 2009). 

Conclusions 

Lists of invasive alien plants (IAPs) are a key issue/tool in effective management of invasive 

non-native species in regions (countries). 

The lists are needed and used for early warning, monitoring, eradication and control, 

education and communication at local, regional and global scales. 

Differences in definitions (concepts), invasive status categories and criteria are reflected in 

lists of IAPs produced in different countries, regions, communities. 

Quantitative criteria of invasiveness and science-based data are needed to minimise 

subjectivity of experts opinions / assessment of invasive status of non-native species. 

The lists have to be updated every 5 to

Brunel S, Schrader G, Brundu G & Fried G (2010) Emerging invasive alien plants for the Mediterranean Basin. 

Bulletin OEPP/EPPO Bulletin 40, 219–238 

CIESM (2007) The Mediterranean Science Commission (2007) Atlas of exotic species in the 

Mediterranean. www.ciesm.org/online/atlas/index.htm. Cited Sept 2010. 

EEA/SEBI2010 (2006) Expert Group on trends in invasive alien species 

EEA (2007) Halting the loss of biodiversity by 2010: proposal for a first set of indicators to monitor progress in 

Europe. European Environment Agency, Technical Report 11/2007 

EEA (2010) Towards an early warning and information system for invasive alien species (IAS) threatening 

biodiversity in Europe. Copenhagen, 2010 - 52 pp. 

Eliáš P (1993) Invasive behaviour of alien annuals. In: Plants invasions – theory and application. Workshop 

Abstracts, Kostelec and Ţernými lesy, p. 7. 

Eliáš P (ed.) (1997) Invasions and Invasive Organisms. Proceedings of the scientific conference on invasions and 

invasive alien species, Nitra, November 2006. Slovak National Committee for SCOPE et SEKOS-Slovak 

Ecological Society, Bratislava, 213 pp. 

Eliáš P (1998) The most important invasive species in Slovakia (Central Europe). In: Gluchov OZ et al (eds) 

Industrial Botanz. Current stage and Perspective of the Development (Promyslova botanika. Stan ta 

perspektiva razvitku). Multipress Doneck, 1998, p. 127-128. 

Eliáš P (2001) Management strategies for introduced alien species escaped into the wild. Livro de resumos do 10 

Simpñsio sobre espécies exñticas (1st Symposium of exotics. Introduction, causes and consequences). 

Lisbon, Portugal, 24th-25th March 2000, p. 22-23. 

Eliáš P (2001) Invasive potential of introduced plant species and possibilities of its estimation (In Slovak with 

English summary). – Životne Prostredie (The Environment), Bratislava, 35(2), 83-86. 

Eliáš P (2003) Invasive species. In: Rydén, L., Migula, P., Andersson, M., (eds.), Environmental Science. The 

Baltic University Press, Uppsala, p. 230-239. – ISBN 91-970017-1-6 

Eliáš P (2005) Invasive plants as environmental weeds. In Slovak. Ţivotné Prostredie }The Environment) 39 4, 

p. 200–203. 

Eliáš P (2006) How many invasive species in Central Europe ? In: Neobiota Conference, Wien, Book of 

Abstracts. 

Eliáš P (2008) How many is invasive plants in Central Europe ? In Slovak. Ecological studies, SEKOS, Nitra 7, 

53-62. 

Eliáš P (2009) Biotic invasions and management of alien species. 1 st Edition. In Slovak. Slovak Agricultural 

University, Nitra. 186 pp. 

EPPO Website (2010) Reporting Service 

http://www.eppo.org/PUBLICATIONS/reporting/reporting_service.htm [Accessed on September 2010]. 

ESIS (2004) European Strategy for Invasive Alien Species. Bern Convention. 

Genovesi P & Scalera R (2007) Towards a black list of invasive alien species entering Europe through trade, 

and proposed responses. Convention on the Conservation of European wildlife and natural habitats. 

Standing Committee 27th Meeting, Strasbourg, 26–29 November 2007. T-PVS/Inf 9 

Genovesi P & Shine C (2004) 'European strategy on invasive alien species.' Convention on the Conservation of 

European Wildlife and Habitats (Bern Convention). Nature and environment, No. 137, Council of Europe 

Publishing (137), p. 1–66. 

SCOPE (2001) Global Strategy for Invasive Alien Species. 

Gollasch S, Minchin D, Rosenthal H & Voigt M (eds) (1999) Exotics across the ocean. Case histories on 

introduced species: their general biology, distribution, range expansion and impact. Logos, Berlin 

IPPC Secretariat (2005) Identification of risks and management of invasive alien species using the IPPC 

framework. Proceedings of the workshop on invasive alien species and the International Plant Protection 

Convention, Braunschweig, Germany, 22-26 September 2003. Rome, Italy, FAO. xii + 301 pp. 

IUCN (2001) Guidelines for the Prevention of Biodiversity loss caused by alien invasive species. December 

2002. 

Love S, Browne M, Boudjelas S, De Poorter M (2000) 100 of the World‘s Worst Invasive Species. A Selection 

from the Global Invasive Species Database. ww.issg.org. Cited September 2010. 

Mack RN, Simberloff D, Lonsdale WM, Evans H, Clout M & Bazzaz F (2000) Biotic invasions: causes, 

epidemiology, global consequences and control. Ecological Society of America, Issues in Ecology, 5, 

Spring 2000, p. 1-20. 

McNeely JA, Mooney HA, Neville LE, Schei P &.Waage JK (eds.) (2001) A Global Strategy on Invasive Alien 

Species. IUCN Gland, Switzerland, and Cambridge, UK. x + 50 pp. 

Mooney HA, Mack RN, McNeely JA, Neville LE, Schei PJ & Waage JK (eds.) (2005) Invasive alien species: 

a new synthesis. SCOPE Report 63. Island Press, Washington, 368 p. 

NOBANIS (2007) North European and Baltic Network on Invasive Alien Species. www.nobanis. org. Cited 18 

September 2007 

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Richardson DM, Pysek P, Rejmanek M, Barbour M G, Panetta FD & West CJ (2000) Naturalization and 

invasion of alien plants. Diversity and distribution 6, 93-107. 

Scherer-Lorenzen M, Elend A, Nollert S & Schulze D (2000): Plant invasions in Germany: general aspects and 

impact of nitrogen deposition. In: Mooney, H.A., Hobbs, R.J. (Eds.), Invasive species in a changing 

world. p. 351-368. Island Press, Washington, 

Sellers E, Simpson A & Curd-Hetrick S (2010) (Last Updated). List of Invasive Alien Species (IAS) Online 

Information Systems. A 'living document' based on a preliminary draft document, prepared for the 

Experts Meeting Towards the Implementation of a Global Invasive Species Information Network 

(GISIN), Baltimore, Maryland, USA, 6-8 April 2004. 

http://www.gisinetwork.org/Documents/draftiasdbs.pdf 

Shine C, Williams N & Gündling L (2000) A guide to designing legal and institutional frameworks on alien 

invasive species. IUCN, Gland, Switzerland Cambridge and Bonn. Xvi + 138 pp. 

Smith IM (2005) EPPO‘s regional approach to invasive alien species. In: IPPC Secretariat. 2005. Identification 

of risks and management of invasive alien species using the IPPC framework. Proceedings of the 

workshop on invasive alien species and the International Plant Protection Convention, Braunschweig, 

Germany, 22-26 September 2003. Rome, Italy, FAO. xii + 301 pp. 

Vilà M, Basnau C, Gollasch S, Josefsson M, Pergl J & Scalera R (2009) One hundred of the most invasive alien 

species in Europe. In: DAISIE Handbook of alien species in Europe. Springer, Dordrecht. P. 265–268 

Wittenberg R & Cock MJW (eds) (2001) Invasive alien species: A toolkit of best prevention and management 

practices. Global Invasive Species Programme, CAB International, Wallingford, Oxon, UK. Xii + 228 pp 

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Monitoring Invasive Alien Plants in the Western Black Sea Region of Turkey 

Necmi Aksoy 1 , Ayşe Kaplan 2 , Neval Güneş Özkan 1 , Serdar Aslan 1 

1 Düzce University Forest Faculty Department of Forest Botany & DUOF Herbarium, 

Beçiyörükler, Düzce, Turkey, E-mail: necmiaksoy@duzce.edu.tr 

2 Zonguldak Karaelmas University Faculty of Art-Science Department of Biology, Zonguldak, 

Turkey 

Introduction 

In this study, information on the distribution of the following invasive alien 

plants in the Western Black Sea Region of Turkey is provided: Abutilon 

theophrasti Medik., Amorpha fruticosa L., Conyza canadensis (L.) 

Cronquist, Rosa multiflora Thumb., Lavatera arborea L., Oenothera biennis 

L., Opunthia ficus-indica (L.) Miller, Phytolacca americana L., Ambrosia 

elatior, Abutilon theophrasti, Amorpha fruticosa, Lavatera arborea. These 

species were found as a new record for the Düzce Region and were 

deposited at the DUOF herbaria. 

As a result of our observations, it was found that these plants could be 

invasive and naturalized in the near future. We discuss their monitoring 

possibilities with pollen data and land observations in the Western Black 

Sea Region. 

Düzce is situated on the Melen River Basin in the Western Black Sea Region of Anatolia. 

It is located in the north of the Elmacık Mountain range and in the south of the Kaplandede 

Mountain. The Düzce region is in the A3 grid square by considering the categorization of 

Davis (1965-88). It is under the influences of the Euro-Siberian, Mediterranean and Irano- 

Turanian phytogeographic regions. The Düzce region shows a transitory character between 

the Black Sea and the Mediterranean climate. Compared to other Black Sea regions, it is less 

rainy in winter and temperatures are lower in winter and summer. No dry period is observed 

in the research area. 

Material and Method 

1. Land survey 

Data from the literature were used to elaborate a detailed database of alien plant species in 

the Düzce region (Flora of Turkey and the East Aegean Islands Vol:1-9 (Davis 1965-1988)). 

This information was updated by local botanists using data from their own field observations 

and collections (The Vegetation of Elmacık Mountain (Aksoy 2006), Flora and Ethnobotany 

of the Akçakoca District (Koca 2003) and the flora of Hasanlar Dam Lake and its 

surroundings (Güneş Özkan 2009). The number of total vascular plants reaches to more than 

one thousand taxa in the Düzce Region (Figure 1). Information from the Düzce and the 

Western Black Sea Region was exclusively obtained from the most recent literature as 

reported above. Herbaceous and woody plant samples including some organs like spores, 

flowers, fruits, cones, buds, leaves, stems and roots were collected as research material. 

Photographs of this material were taken and some information was noted like habitus, 

coordinate, altitudes, etc. Collected samples were dried in a wooden plant press. Dry samples 

were put in the freezer during 3 days for disinfection. The samples were then identified using 

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a stereo microscope. Plants collected from the study area were deposited in the herbarium of 

the Forest Faculty of the Düzce University (DUOF). 

Figure 1 - Map of Düzce province 

2. Airborne pollen monitoring 

A Burkard Seven-day Recording Volumetric Spore Trap (BST) and Durham 

gravimetric sampler were used to monitor the airborne pollen and fungal spores at the city 

center (Figure 2) and the University Campus (Figure 3). The Durham sampler was installed 

on the roof of the Yimpaş Holding building in 2006 and the Burkard sampler was installed 

on the roof of the Forest Faculty in 2007 at 9 m above ground level for two years. During 

the investigation period, Pinus, Gramineae, Corylus, Ambrosia elatior, Carpinus, 

Fraxinus, Cupressus, Chenopodiaceae, Morus, Quercus, Fagus, Juniperus, Platanus, 

Ostrya, Abies, Alnus, Acer, Castanea were observed as dominant taxa in Düzce 

atmosphere (Serbest et al., 2008). 


The species have been sorted according to invasive behaviour (from higher to lower). 

Within the most aggressive, species have been sorted by their morphology (herbaceous, 

woody, habitat and so on). These species with the invasion scale (1. Low invasive, 2. 

Invasive, 3. Highly invasive 4. Extremely invasive) are presented in Table 1. 

Weekly Ambrosia elatior L. pollen dispersal per cm 2 in 2006 by using the Durham sampler 

and per m 3 in 2007 by using the Hirst Burkard Trap. Monthly Pollen concentrations reached a 

maximum level in August (53 g/cm 2 in 2006, 635 g/m 3 in 2007). Weekly pollen 

concentrations reached a high level at the 34 th week (41 g/cm 2 in 2006, 497 g/m 3 in 2007). 

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The total number of pollen grains was 98 g/cm 2 in 2006, 1174 g/m 3 in 2007 (Table 2, Table 3, 

Figure 4). 

Table 1 - List of alien plants considered as invasive in the Düzce and the Western Black Sea 

Regions (1. Low invasive, 2. Invasive, 3. High invasive 4. Extremely invasive) 

Plant Name Habitat 

Abutilon theophrastii 

Medik., Malvaceae 


(Miller) Swingle, 

Simaroubaceae 

Ambrosia elatior L., 

Asteraceae 

Amorpha fruticosa L., 

Leguminosae 

Conyza canadensis 

(L.) Cronquist, 

Asteraceae 

Rosa multiflora 

Thunb. ex Murr., 

Rosaceae 

Lavetera arborea L., 

Malvaceae 

Oenothera biennis L., 

Onagraceae 

Opuntia ficus-indica 

(L.) Miller, Cactaceae 

Phytolacca americana 

L., Phytolaccaceae 

Sandy, ruderal areas 

railroad 

embankments, 

highway medians, 

fencerows, and 

roadsides 

Damp acid grassland 

near coast. 

Woodland garden; 

sunny edge; dappled 

shade 

In moist conditions, 

often near sea costs 

and weed of 

cultivation 

Dense woods, 

prairies, along stream 

banks and 

roadsides and in open 

fields and pastures 

Determination 

Method 

Field trip 

Field trip 

Pollen 

monitoring + 

field trip 

Field trip 

Field trip 

Field trip 

Coasts Field trip 

Meadow; cultivated 

beds 

Dry, stony soils, often 

near villages. 

Field trip 

Field trip 

Slopes, fields, scrub Field trip 

Destruction 

Property 

Invades near 

fields. 

Invades 

cemeteries, 

various natural 

areas 

Invades ruderal 

areas, roadsides 

and parks 

Invades Parks, 

natural areas and 

ruderal areas 

Invades ruderal 

areas and near 

fields 

Invades hillside 

pastures, and 

roadsides to 

forest edges 

Invades Sea 

sides, dune areas 

and rocky slopes 

Invades 

roadsides, 

ruderal areas and 

parks 

Invades 

roadsides, stony 

slopes and near 

living places. 

Invades 

roadsides, near 

field areas and 

parks 

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Degree 


Invasion 

1 

4 

3 

3 

4 

3 

2 

2 

1 

4 

306

Figure 2 - The Durham sampler located on 

the roof of the Yimpaş Building 

Figure 3 - Burkard Spore Trap (BST) on 

the roof the Forest Faculty Building 

Ailanthus altissima, Conyza canadensis and Phytolacca americana have been described as 

invasive species Ambrosia elatior, Amorpha fruticosa and Rosa multiflora have high invasive 

characters in curben parks and natural woodlands. Especially, Ambrosia elatior is widespread 

in the parks in the Düzce province. Phytolacca americana is occurs at the hedge of hazelnut 

tree plantation areas. Ambrosia elatior was firstly described by airborne pollen monitoring 

system after having been collected during a field trip in Düzce Univeristy Campus and Parks 

of Düzce City. 

Table 2 - Weekly Ambrosia elatior pollen dispersal per cm 2 in 2006 and per m 3 in 2007 by 

using Durham sampler and Hirst Burkard Trap. 

Weeks 31 32 33 34 35 36 37 38 39 40 41 42 Total 

2006 2 0 2 41 10 10 28 0 2 2 1 0 98 g/cm 2 

2007 22 0 19 497 119 122 330 0 28 22 15 0 1174 

g/m 3 

Table 3 - Monthly Ambrosia elatior pollen concentration in 2006 and 2007 by using 

gravimetric and volumetric methods, respectively. 

Months 

Methods 

July Aug Sep Oct Nov Dec Total 

Gravimetric 

(1 cm 2 2 53 42 1 - - 98 grains/cm 

) 

2 

(2006) 

Volumetric 

(1m 3 ) (2007) 

22 635 502 15 - - 1174 grains/m 3 

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Figure 4 - Ambrosia elatior pollen grains. 

Aknowledgements 

Field trip study was sponsored by the Düzce University, Scientific Research Project (No: 

2008.02.01.016) and airborne pollen monitoring study was supported by the Zonguldak 

Karaelmas University, Scientific Research Project (No: 2007-13-06-07). 

References 

Aksoy N (2006) The Vegetation of Elmacık Mountain, İ.Ü. Science Institute, Forest Botany, PhD thesis, 

İstanbul (TR). 

Davis PH (ed.) (1965-88) Flora of Turkey and the East Aegean Islands, Volume: 1-10 Edinburgh Universty 

Press, Edinburgh (UK). 

Güneş Özkan N (2009) The flora of Hasanlar Dam Lake and its surroundings, Düzce University, Science 

Institute, MSc thesis, Düzce (TR). 

Koca A (2003) Flora and Ethnobotany of the Akçakoca District, Hacettepe University, Science Institute, 

Department of Biology, MSc thesis, Ankara (TR). 

Serbes AB, Kaplan A, Aksoy N, Özdoğan Y & Güneş N (2008) Düzce İli Atmosferinin Polen Analizi, Ulusal 

Hava Kalitesi Sempozyumu (30-31 Mayıs 2008) Konya (TR) 

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308

Alien Plant Species in the Western Part of Turkey: Assessing their Invasive Status 

Emin Ugurlu 1 & Roberto Crosti 2 

1 Department of Biology, Celal Bayar University, Manisa, Turkey, 

E-mail: emin.ugurlu@bayar.edu.tr 

2 c/o ISPRA Dipartimento Difesa della Natura Tutela biodiversità Via Curtatone 3 - 00185 

Roma, Italy 

The flora of the Mediterranean Basin contains about 24 000 plant species in a surface area of 

about 2.3 million km 2 , that is 10% of all known plant species in a quite small area; In contrast, 

non Mediterranean Europe covers about 9 million km 2 but has only around 6 000 plant 

species. 

According to the Flora of Turkey, more than 9 000 species occur in the country of which 

approximately 1.5% are alien species. 

The Mediterranean type climate region of Turkey also has a very rich flora. In spite of, or due 

to, flora species richness many alien plants native from South Africa, Central and South 

America and North America occur in the region. For many alien species, however, the 

invasive status is unknown. 

This paper deals with the ecological features, occupancy and distribution of alien plants 

occurring in the Mediterranean Western part of Turkey (Western Anatolia). It is also an 

attempt to review the status of the alien plant species in order to assess the invasiveness, the 

stage in the invasion process, and the degree of naturalization of these species. 

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Invasive alien plants in Armenia 

Kamilla Tamanyan & George Fayvush 

Institute of Botany, National Academy of Sciences of Armenian, Acharyan str. 1, Erevan 

0063, Armenia, E-mail: ktamanian@yahoo.com, gfayvush@yahoo.com 

Introduction 

Preliminary estimation results of the threat of invasive alien plants to the 

natural ecosystems and biodiversity in Armenia is given. The problem of 

invasive alien plants in Armenia used to be underestimated. It was 

considered that due to the mountainous and indented landscapes and the 

absence of big plain territories, invasive alien plants could not harm natural 

ecosystems. By our efforts, the attitude towards the problem of invasive 

species has changed. Our research has shown that in Armenia one invasive 

alien plant cannot occupy large territories. Actually, a huge number of 

invasive alien plants are distributed in suitable habitats for them, and occupy 

relatively small areas by now, but all together they occupy a lot of space. 

The list of species requiring immediate attention contains: invasive alien 

plants that spread very fast, penetrate natural ecosystems and are considered 

as a real threat to natural ecosystems (for example Ailanthus altissima, 

Silybum marianum); species known as invasive in other regions of the world 

that enlarge their distribution, but do not show their invasive potential in 

Armenia yet (for example Ambrosia artemisifolia, Robinia pseudoacacia); 

native plant species that have enlarged their distribution range in the last 

years and represent a real threat to natural ecosystems and biodiversity 

nowadays (for example Astragalus galegiformis, Onopordum armenum, 

Tanacetum vulgare). 

Invasive alien plants are now one of the greatest threats to natural ecosystems and their 

control is one of the priorities in nature conservation. Until now, the problem of invasive 

species was practically not under consideration in Armenia. Within the last 50 years segetal 

flora and vegetation of the republic was investigated at different levels of detail. There were 

no dedicated investigations carried out on invasive alien plants. New species detected on the 

territory of Armenia with herbarium sample were stored in the herbarium of the Institute of 

Botany of the Republic of Armenia (ERE). Species that were specially introduced and used 

for town and settlement greenery or artificial afforestation and that further penetrated into 

natural ecosystems were totally out of attention. The first national report on Armenian 

biodiversity (1999) had a small section dedicated to invasive alien species. A small list of 

species was provided, which is now almost totally revised by the authors of this article. 

The main reason for this lack of studies on invasive alien plant in Armenia is probably due 

to the underestimation of the problem by the scientific community and governmental 

structures. It was considered that due to the mountainous and indented landscapes of the 

country and the absence of big plain territories, invasive alien plants could not harm natural 

flora and vegetation of the republic. 

Thanks to our efforts, the attitude towards invasive alien plants in Armenia changed a little. 

In 2005, a scientific research topic was approved and funded by the government, that included 

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the study of the spread of the main invasive alien plants in the territory of Republic. This 

funding is of course insufficient to get an exhaustive knowledge of the situation on invasive 

alien plants, but the first step is done and field investigations started. 

Invasive alien and spreading native plants in Armenia 

According to the results of a preparatory work (through literature and herbarium materials 

review), as well as of fields investigations, we created a list of plant species that would 

require immediate attention. It includes about 100 species and contains both species known as 

invasive in other regions of the world that are recently recorded in Armenia, and native 

spreading plants (table 1). Our investigations showed that in the mosaic-like conditions of the 

mountains of Armenia, these species cannot occupy large territories. Actually, a huge number 

of invasive alien plants are distributed in suitable habitats. About 100 species occur in 

disturbed areas or penetrated into natural ecosystems. Each of these species occupies rather 

small areas, but all together they occupy considerable space. Some of these species were 

introduced as ornamentals (Fayvush, 2008; Tamanyan, 2008). 

The species of most concern is currently the alien tree Ailanthus altissima, which is 

spreading in natural ecosystems in the north and south of Armenia, as well as in disturbed 

ecosystems of the central part of the country. Robinia pseudoacacia penetrates into natural 

ecosystems rather intensively in North Armenia. Silybum marianum spreads very intensively 

in North and South Armenia and needs constant control. Other species that occur only 

occasionally (Ambrosia artemisifolia, Galinsoga parviflora, Galinsoga ciliata, Sphaerophysa 

salsula, etc.) require constant control to prevent their spread. However, indigenous spreading 

species (Astragalus galegiformis, Onopordum armenum, different Cirsium, Carduus, 

Tripleurospermum species, Cardaria draba, Cardaria boissieri, Geranium tuberosum and 

many others), especially those growing plentifully in abandoned fields, require most attention, 

as they form reserves of seed and penetrate into natural ecosystems. 

There is a big concern connected with modern agricultural system in Armenia. Small 

individual economies, which were established during the land privatization in the 1990s, have 

become unprofitable in the majority of cases. As a result on the one hand the process of 

enlargement of agricultural economies started, and on the other hand big territories of 

agricultural land became abandoned. They became a source of conservation and distribution 

of seeds of many invasive species like Cirsium arvense, Cirsium incanum, Cirsium vulgare, 

Geranium tuberosum, Leucanthemum vulgare, and others. They are intensively spreading in 

abandoned fields and penetrating into natural ecosystems. 

The investigation of potentially invasive alien plants in Armenia may be very important for 

countries around the World. Biological control of alien pests is commonly used in many 

countries worldwide. Being one of the centers of biodiversity Armenia may provide potential 

material (insects, fungi and other) for fighting species invading natural ecosystems both in the 

country and abroad. It should be mentioned that many invasive alien plants in Armenia have 

the same potential and are pollutant in natural ecosystems in other countries. For example, 38 

species in the Armenian flora are very dangerous invasive alien species in North America, and 

4 Armenian plant species are included in the list of ―100 of the World‘s Worst Invasive Alien 

Species‖ (ISSG/IUCN). 

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Table 1 - Invasive alien and native spreading plants that are a potential threat for natural 

ecosystems of Armenia 

Species Status Threat* 

Acalypha australis Potentially invasive Spreading in abandoned fields and semi-deserts - 

species 

1 

Acer ibericum Spreading species Intensively spreading in arid and semi-arid 

communities - 3 

Acer negundo Potentially invasive Independently spreading in towns and settlements, 

species 

more rarely in disturbed habitats - 2 

Achillea filipendulina Spreading species Intensively spreading in disturbed habitats - 3 

Acroptilon repens Spreading species Plentiful on disturbed habitats, abandoned fields - 

2 

Ailanthus altissima Invasive alien species Intensively penetrates natural ecosystems - 4 

Alliaria petiolata Spreading species Widespread in Armenian forests, but not plentiful 

and do not represent an immediate threat - 1 

Amaranthus 

Spreading species Widespread in Central Armenia, especially in 

retroflexus 

disturbed areas and in towns - 2 

Ambrosia 

artemisiifolia 

Potentially invasive 

species 

First found in the north of Armenia in1983 

(Gabrielian & Tamanyan 1985, Avetisyan 1995), 

currently spreading in north and central regions of 

Armenia - 2 

Anchusa arvensis Spreading species Intensively spreading in disturbed habitats - 3 

Anemone fasciculata Spreading species Intensively spreading in sub-alpine meadows - 2 

Anthemis cotula, Spreading species Intensively spreading in meadows, abandoned 

Anthemis triumfettii 

fields and edges of forests - 4 

Arctium palladinii Spreading species Intensively spreading on disturbed habitats, 

especially on forest glades - 2 

Artemisia vulgaris Spreading species Intensively spreading in disturbed habitats - 2 

Astragalus 

Spreading species Intensively spreading on forest edges, roadsides, 

galegiformis 

steppes in North and Central Armenia - 4 

Bunias orientalis Spreading species Intensively spreading in ruderal habitats, 

Caltha palustris Spreading species 

roadsides, fields - 2 

Intensively spreading in wetlands in middle and 

upper mountain belts - 2 

Cardaria boissieri, Potentially invasive Intensively spreading in disturbed habitats, 

Cardaria draba species 

abandoned fields - 3 

Carduus hamulosus, Spreading species Intensively spreading in disturbed habitats - 2 

Carduus nutans 

Carthamus 

Spreading species Intensively spreading on disturbed habitats and 

turkestanicus 

penetrates into natural ecosystems in semi-desert 

and steppes - 3 

Centaurea behen Spreading species Intensively spreading in steppe communities - 3 

Centaurea diffusa Potentially 

species 

invasive Weed in cereals fields, penetrating into steppes - 1 

Centaurea iberica Spreading species Intensively spreading in disturbed habitats in arid 

and semi-arid zones - 3 

Centaurea solstitialis Potentially 

species 

invasive Widespread in disturbed habitats - 3 

Chamaesyce maculata Spreading species Widespread in disturbed habitats in semi-desert - 

1 

Chenopodium botrys Spreading species Widespread in disturbed habitats - 1 

Chondrilla juncea Potentially 

species 

invasive Widespread in disturbed habitats - 3 

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Circaea lutetiana Spreading species Intensively spreading in disturbed forest habitats - 

2 

Cirsium anatolicum, Spreading species Intensively spreading in disturbed habitats, 

Cirsium arvense, 

especially in abandoned fields – 2-3 

Cirsium congestum, 

Cirsium incanum, 

Cirsium vulgare 

Clematis orientalis Spreading species Intensively spreading along rivers of the Ararat 

valley - 3 

Conium maculatum Spreading species Intensively spreading in disturbed habitats, the 

spread in sub-alpine communities is registered - 3 

Consolida orientalis Spreading species Intensively spreading in steppes, semi-deserts, 

very plentiful in abandoned fields - 2 

Conyza canadensis Invasive species Intensively spreading in forests, especially in 

disturbed areas - 1 

Crupina vulgaris Spreading species Intensively spreading in steppes - 1 

Descurainia sophia Spreading species Growing mainly in ruderal habitats, penetrating 

forests and meadows - 1 

Echinocystis lobata Potentially 

species 

invasive Now is rather rare in North Armenia - 1 

Erigeron acris, 

Erigeron annuus 

Spreading species Intensively penetrating steppes and meadows - 1 

Erodium cicutarium Spreading species Intensively spreading in disturbed habitats in arid 


Euclidium syriacum Spreading species Intensively spreading in disturbed habitats in arid 


Euphorbia 

Spreading species Intensively spreading in steppe pastures by first 

seguieriana 

signs of overgrazing - 2 

Galinsoga ciliata, Potentially invasive Widespread in towns, settlements; not registered 

Galinsoga parviflora species 

yet in natural ecosystems - 1 

Geranium tuberosum Spreading species Intensively spreading in abandoned fields - 2 

Glechoma hederacea Spreading species Intensively spreading in disturbed forest habitats - 

2 

Gleditschia 

Potentially invasive Spreading along irrigation channels in the Ararat 

triacanthos 

species 

valley - 2 

Goebelia 

Spreading species Intensively spreading in wetlands, in abandoned 

alopecuroides 

fields in the Ararat valley and the Vayots Dzor 

province - 3 

Helianthus tuberosus Potentially invasive Cultivated on small squares, rarely occur in 

species 

ruderal and disturbed habitats - 1 

Heracleum 

Spreading species Spreading intensively in disturbed habitats in 

antasiaticum, 

Heracleum 

schelkovnikovii, 

Heracleum 

sosnowskyi, 

Heracleum 

trachyloma 

humid and semi-humid zones – 2-3 

Hyppophae 

Spreading species Was introduced in different regions of Armenia 

rhamnoides 

(mainly in the Sevan basin), now is spreading in 

natural habitats - 3 

Impatiens glandulifera Potentially 

species 

invasive Found in North Armenia, needs special control - 1 

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Iva xanthifolia Potentially 

species 

invasive Found in West Armenia, needs special control - 1 

Leontodon hispidus Spreading species Spreading in steppes and meadows - 2 

Lepidium latifolium, 

Lepidium ruderale 

Spreading species Spreading in disturbed habitats - 2 

Leucanthemum Spreading species Intensively spreading in abandoned fields, 

vulgare 

penetrates meadow and steppe communities - 4 

Lythrum salicaria Potentially 

species 

invasive Widespread in wetlands - 2 

Onopordum 

Potentially invasive Spreading in disturbed habitats - 1 

acanthium 

species 

Onopordum armenum Spreading species Very intensively spread in disturbed habitats and 

penetrates into natural habitats, especially in 

central and west parts of Armenia. Enlarged a lot 

its area in the last years - 4 

Papaver 

Spreading species Intensively spreading in steppe and meadow 

macrostomum 

communities - 2 

Peganum harmala Spreading species Spreading in disturbed habitats - 1 

Picris hieracioides Spreading species Spreading in disturbed habitats - 1 

Polygonum alpinum Spreading species Intensively spreading in sub-alpine communities - 

2 

Populus alba Spreading species Spreading in wetlands - 1 

Rhynchocorys 

orientalis 

Spreading species Intensively spreading in meadows - 3 

Robinia pseudoacacia Invasive species Rarely occcurs in natural communities, not threat 

yet. Very 

countries - 3 

intensive spread in neighboring 

Salix caprea Spreading species Intensive spread in disturbed forest habitats - 2 

Sanicula europaea Spreading species Intensive spread in disturbed forest habitats - 2 

Scandix stellata Spreading species Intensive spread in abandoned fields, penetrates 

meadow and steppe communities - 2 

Siegesbeckia 

orientalis 

Spreading species Spreading lower mountain belt - 1 

Silybum marianum Invasive species Enlarged a lot its area in South and North 

Armenia within last years - 4 

Solidago virgaurea Potentially invasive Widespread in forest and meadow communities - 

species 

1 

Sonchus oleraceus Spreading species Spreading in wetlands - 1 

Sphaerophysa salsula Invasive species First recorded in Armenia in 1990 (Zakharian & 

Fayvush 1991); within those years it spread in the 

Ararat valley - 1 

Spinacia tetrandra Spreading species Spreading in semi-deserts - 1 

Tagetes minima Invasive species Was introduced as an ornamental plant, now 

spreads in disturbed ecosystems - 1 

Tanacetum 

parthenium 

Spreading species Spreading in steppes - 2 

Tanacetum vulgare Invasive species Enlarged a lot its area in the whole of Armenia 

within last years - 3 

Tribulus terrestris Spreading species Intensively spreading in disturbed habitats in arid 


Tripleurospermum Spreading species Intensively spreading in meadow and steppe 

caucasicum, 

communities, especially because of overgrazing - 

Tripleurospermum 

transcaucasicum 

4 

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Veratrum album Spreading species Intensively spreading in meadow associations 

because of overgrazing - 2 

Verbascum 

Spreading species Intensively spreading in abandoned fields and 

georgicum, 

disturbed habitats, penetrate steppes - 2 

Verbascum 

Verbascum 

paniculatum 

laxum, 

Xanthium italicum, Potentially invasive Widespread in disturbed habitats - 2 

Xanthium spinosum, species 

Xanthium strumarium 

Xeranthemum Spreading species Intensive spread in steppes and semi-deserts, 

squarrosum 

especially in disturbed habitats - 2 

4 - Invasive or spreading species intensively penetrating into natural ecosystems; 

3 - Invasive or spreading species widely distributed in disturbed habitats, and rarely penetrating into 

natural ecosystems; 

2 - Invasive or spreading species distributed in disturbed habitats, but not recorded in natural 

ecosystems yet; 

1 - Plants with great invasive potential (known as invasive in other countries), but not threatening 

natural ecosystems of Armenia yet. 

References 

Avetisyan V (1995) Genus Ambrosia. In: Flora of Armenia (ed. Takhtadjan A L), 9, 494 (in Russian). Koeltz 

Scientific Books, Koenigstein. 

Biodiversity of Armenia. First National Report. (1999).Yerevan. 

Fayvush G (2008) Investigation of invasive plant species in Armenia. Abstr. of 5 th European conference on 

biological invasions ―Neobiota: towards a synthesis‖, Prague (Czech Republic), 23-26 September 2008, 

p.72. 

Gabrielian E & Tamanyan K (1985). New genus and rare species for the flora of Armenia. Biological journal of 

Armenia 38, 164-166 (in Russian). 

Tamanyan K (2008) Invasive plant species and agriculture in Armenia. Abstr. of 5 th European conference on 

biological imnvasions ―Neobiota: towards a synthesis‖, Prague (Czech Republic), 23-26 September 2008, 

p. 114. 

Zakharian M & Fayvush G (1991) Sphaerophysa (Fabaceae) - a new genus for the flora of Armenia. Biological 

journal of Armenia 44, 53-54 (in Russian). 

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Invasive aquatic plants in the French Mediterranean area. First results of a French 

survey 

Emilie Mazaubert 1 , Alain Dutartre 1 , Nicolas Poulet 2 

1 REBX, Cemagref, 50 avenue de Verdun, 33612 Cestas Cedex, France, E-mails : 

emilie.mazaubert@cemagref.fr; alain.dutartre@cemagref.fr 

2 Onema-DAST, Direction Générale, "Le Nadar" Hall C, 5 square Félix Nadar, 94300 

Vincennes, France nicolas.poulet@onema.fr 

Introduction 

Following the request of the French Working Group on Biological Invasions 

in Aquatic Environments (BIAE), a survey has been launched to assess the 

current situation of the management of biological invasions in aquatic 

environments in France. Since October 2009, we gathered information about 

invasive alien plant presence, impacts and effectiveness of control attempts. 

This article summarizes the results obtained for invasive alien plants in the 

French Mediterranean region. 

Out of 27 responses, the majority of records are affiliated with watershed 

local authorities or associations. The most common species recorded in this 

survey are similar to those most cited at the national scale, i.e. the water 

primrose (Ludwigia sp.) and the Japanese knotweed, (Fallopia sp.). 

We also analyzed the different types of impacts and management actions 

associated with each plant species recorded. The results are similar to those 

obtained for the whole French territory. The management costs were also 

examined. 

A second phase of investigation should help clarify all this data and refine 

the analysis and interpretation. 

Increasing numbers of plant and animal species are introduced intentionally or accidentally 

by humans in areas often very remote from their native location. These introductions are 

facilitated by globalization, increased trade and transcontinental communications and travel. 

A proportion of these introduced species can adapt to their new environment and under 

certain conditions become invasive. (Richardson et al., 2000). 

The problems caused by invasive species are due to their ability to grow rapidly and 

reproduce prolifically, and thus to colonize space, often to the detriment of native species. 

This phenomenon often comes along with negative impacts on the environment and on human 

activities (fishing, boating, etc.) but also on human health (transmission of diseases, allergies, 

etc.) that can have significant economic consequences. (Pimentel et al., 2005; Kettunen et al., 

2008) 

For all these reasons, the problem of invasive alien species (IAS) is of growing concern for 

researchers and institutions tasked with the management of natural resources (Mazaubert, 

2008). 

Thus, within the framework of an agreement between the French National Agency for 

Water and Aquatic Environments (Onema) and the Cemagref (Institute for Research in 

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Science and Technology for the Environment), a Working Group on Biological Invasions in 

Aquatic Ecosystems (BIAE) was instituted in January, 2009. Under the coordination of the 

Onema, this working group gathers managers, institutional investors and researchers. 

The main objectives of the WG BIAE are: 

- To generate a set of guidelines for the management of biological invasions in aquatic 

ecosystems 

- To develop operational tools of species management intended for managers and policy 

makers 

- To define strategic longer term research issues 

The discussions of this group include: 

- Identification of environmental, economic and social stakes of IAS management, 

- Identification of the involved actors and the mobilizable capacity for the implementation of 

coordinated actions, 

- Definition of the steps required to properly meet the challenges, 

- Conception of tools and protocols for the implementation of the national strategy on IAS, 

(Muller & Soubeyran, 2010) 

- National contribution at the European level (European Water Framework Directive, 

standardization, etc.). 

The management representatives in the working group felt that management issues were 

not adequately represented in these original objectives. They insisted on the needs and 

expectations of local managers, including providing recommendations for practical 

interventions. As a consequence of these comments, a survey on invasive alien species in 

aquatic environments and their management was initiated. 

The objectives of this survey are: 

- To answer to this specific request of the members of the working group by: creating a 

synthesis of management actions on aquatic alien species already undertaken in France, 

providing access to already existing results and sharing knowledge, 

- To allow exchanges between managers and to participate, in the longer term, to the 

realization of maps of management actions at the national level. 

Thus, this survey includes information on managers and users of aquatic environments, on 

the territories they have to manage, on the invasive alien animal and/or plant species found, 

and on the management actions undertaken and their efficiency. 

The final objective of this survey was to produce a synthesis of the management 

interventions of invasive aquatic species in France. It also aims to identify the methods most 

commonly used for a particular species, their cost and their efficiency. We aim to gather the 

maximum amount of information possible for dissemination on a large scale in order to 

optimize future management actions. 

The survey 

To achieve the objectives described above, the volume of data required from this survey 

dedicated to managers and/or users of the aquatic environment had to be very large; it was 

therefore decided to conduct a 2-step survey. 

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The first step, currently underway, includes a questionnaire to collect all the information 

available about the observer, the institutional structure to which he/she is affiliated and the 

territory concerned with regards to the observation. For each species, information about the 

identification is required as well as the habitats colonized, the frequency of invasion, the 

presumed impacts of the IAS and the management methods used. This first phase also offered 

the opportunity for observers to indicate if they already had provided information on this 

subject and, if necessary, for which purpose. This prevented observers from providing the 

information twice. 

A sufficient number of responses was needed to conduct complete analyses and to have an 

overall view of the distribution of species and management actions at the national scale; the 

survey was distributed as widely as possible. Members of the WG BIAE had in charge to 

relay the questionnaire to various organizations and institutions (e.g. the Water Agencies, 

natural reserves, Fishing Federations, etc.). 

This first step helped in defining new targets for the questionnaire. After contacting the 

observers, the second step was to collect various information about the management methods, 

their effectiveness and their cost. We expected that this approach would also allow further 

identification of other potential cooperating agencies. (Mazaubert & Dutartre, 2010) 

First exploitation results on invasive plant species in the Mediterranean region 

Although the WG BIAE is in charge of both invasive alien animals and plants, only the 

results on invasive alien plants in the French Mediterranean region were analysed. These 

results can be compared with results from the whole French area. 

General Information 

The French Mediterranean region includes three administrative regions (see Figure 1). We 

sent the questionnaire to several tens institutions during six months. We receive back 2, 11 

and 14 responses respectively for Corsica, Languedoc-Roussillon and Provence-Alpes-Côte 

d‘Azur; i.e. 27 responses were obtained for the Mediterranean French region. This 

corresponded with 10% of all current responses to the survey. 

Figure 1 - Administrative regions of the Mediterranean area in France 

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Moreover, distribution of the survey had to concern all agencies or institutions confronted 

with the presence and impact of invasive alien species and / or having already realized the 

management actions on these species. The diversity of the respondents was significant 

(associations, local authorities, federations, parks, etc.) (Mazaubert & Dutartre, 2010). 

Most observers in the Mediterranean regions belong to watershed local authorities or 

associations (see Figure 2) and those observers gathered under the label "Other" are part of 

the public institutions (MNHN and VNF) or a research centre. 

7 

6 

5 

4 

3 

2 

1 

0 

5 

3 

1 1 1 1 

Figure 2 - Number of responses by type of institutions in the French Mediterranean region 

Information species by species 

In the first part of the questionnaire, respondents were asked to indicate, from lists of 

proposed species, the species present in their territory, and to provide an indication of the 

frequency of observations of different species. This frequency can correspond to both an 

extensive geographical distribution of these species and/or to species better identified by the 

observers for various reasons (because they are more visible in ecosystems, cause 

greater/more numerous/more easily identifiable impacts; Mazaubert & Dutartre, 2010). 

Among the 18 species listed in the questionnaire, 15 were cited as present in the 

Mediterranean region (see Figure 3). 

The survey allowed to give information on additional species observed. Among the 

additional species listed, only Baccharis halimifolia can be considered as an alien aquatic 

species. This species is taken into account in a further detailed analysis in this article. 

The following questions were asked per species in order to gather detailed information. 

Among these issues, some concern the impacts caused by the species while other questions 

were related to management interventions (see Figure 3). 

Figure 3 shows the discrepancy between knowledge of the presence of a species and more 

detailed information about the impacts and management for that species. Indeed, for half of 

the species whose presence is reported in the Mediterranean region, information on the 

presence is not accompanied by detailed information on the impacts or the management. 

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6 

3 

319

Of the 16 alien aquatic plant species listed as present in the Mediterranean region, water 

primerose (Ludwigia sp. and knotweed (Fallopia sp.) were the most documented species. 

Both were also better represented at the national level. 

The presence of black locust (Robinia pseudoacacia) and common ragweed (Ambrosia 

artemisiifolia) was also frequently mentioned, but the details are scarce. The same 

observation can be made at national level for the black locust (Robinia pseudoacacia). 

Ambrosia artemisiifolia 

Azolla filiculoides 

Baccharis halimifolia 

Buddleja davidii 

Carprobrotus sp. 

Caulerpa taxifolia 

Egeria densa 

Elodea sp. 

Fallopia sp. 

Heracleum mantegazzianum 

Impatiens sp. 

Lagarosiphon major 

Ludwigia sp. 

Myriophyllum aquaticum 

Polygonum polystachyum 


Figure 3 - Number of observations 

0 2 4 6 8 10 12 14 16 

Presence in Mediterranean 

Region 

Impacts 

Management 

Impact of species 

It was important to gather presence data as well as management data about the invasive 

alien species in order to assess the impacts caused by the plant species on the aquatic 

environment. 

To facilitate manager response and to structure subsequent analysis of the data (Mazaubert 

& Dutartre, 2010), the questionnaire presented several types of possible impacts: 

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environmental characteristics (flow modifications, water quality modifications, shoreline 

erosion, bottom erosion), biodiversity (competition with native species, predation of native 

species, a vector of pathogens, standardization of landscape) and the use of the environment 

(access, hunting, fishing, commercial or recreational navigation, agriculture, bathing, 

irrigation, industrial water intake, drinking water). 

Descriptions of the generated impacts are provided for seven plant species in the 

Mediterranean region (see Figure 3). 

As for the national level, the results of the survey show that the impacts of invasive plants 

are numerous and varied (see Figure 4). 

29% 

0% 

4% 

38% 

16% 

24% 

14% 

On environmental features 

0% 

57% 

On biodiversity 

58% 

Flow modifications 

Water quality 

modifications 

Shoreline erosion 

Bottom erosion 

Competition with native species 

Predation of native species 

Pathogen vector 

Standardization landscape 

On the use of the environment 

0% 8% 4% 4% 

0% 

8% 

36% 

Environment access 

Hunting 

Fishing 

Navigation (commercial or 

recreational) 

Agriculture (direct impact on 

crops) 

Bathing 

Irrigation 

Industrial water intake 

Drinking water 

Figure 4 - Impacts of invasive plants in the French Mediterranean area 

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In the Mediterranean region, flow modifications caused by spread of plant population is 

the main impact identified while at the national level, flow and water quality modifications, 

and shoreline erosion have the same proportions of quotations. This difference could be 

explained by the lower diversity of species for which information is provided on the impacts 

in the Mediterranean region or by higher hydrological sensitivity of the aquatic Mediterranean 

waterbodies. However, the main impacts on biodiversity (competition with native species and 

unified landscape) and on use (accessible environments and fisheries) in the Mediterranean 

regions are similar to the national level. 

At the scale of the Mediterranean region as in the case nationally, these impacts can be 

partly explained by the development of dense plant beds in stagnant waterbodies which can 

cause asphyxia or large deposits of organic material or plant proliferation causing bank 

erosion and reduced accessibility for users. On the other hand, the impacts can be linked 

together: e.g., a plant species that thrives in the body of water can reduce the ecological 

quality and cause a decrease in the presence of fish and thus have a negative effect on fishing 

activities. 

Species management 

Different modalities of management of alien plant species were proposed in the 

questionnaire: mechanical intervention (e.g. grubbing, clearing, dredging), manual 

intervention, biological control (e.g. grazing), physical regulations (e.g. drought, shading, 

filters), thermal and chemical treatment or "other" (requiring clarification). 

Descriptions of generated impacts are provided for each of the eight plant species in the 

Mediterranean region for which the information is detailed (see Figure 3). 

Different methods can be used for the management of the same species. 

A comprehensive analysis of the relative use of different management techniques was 

realised for the group of these plant species (see Figure 5). 

4% 

7% 

7% 0%4% 

52% 

26% 

Figure 5 - Invasive plants management methods 

Mechanical 

interventions 

Manual interventions 

Biological regulation 

Physical control 

Chemical or thermal 

treatment 

Renaturation 

waterbodies 

Other (scarification for 

Ambrosia artemisiifolia) 

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As at the national level, the management methods most often used for plants are manual 

and mechanical interventions. 

Cost of management actions 

We asked respondents to provide an estimate of the cost of managing invasive alien 

species ("Cost in Euros associated with the management of these species per year (all 

methods)"). It was not our intention to obtain specific information about a species or a 

management approach. Rather, a response and an estimate of value were considered as 

sufficient. This provides an estimate of the cost of management. (Mazaubert & Dutartre, 

2010). 

Of the 27 responses in the Mediterranean region, only 12 included data about costs of 

management, this represents less than half of the observations in this region and only 4% of 

the observations at the national level. 

The range of unit costs reported in the responses of the Mediterranean region is from € 0 to 

€ 80,000 and a total annual sum is € 253,000, which represents about 8% of the total sum 

calculated at the national level. 

The poor response numbers probably lead to a very important underestimation of the actual 

costs of managing invasive alien species in aquatic environments. Even if some individual 

answers may correspond to an effective cost, responses currently available do not provide a 

complete picture. As a matter of fact, these responses do not cover the whole country and we 

could not determine how representative these responses are. Moreover, it is not possible to 

determine whether the amounts listed include all costs that may be involved in the 

management of these species (equipment, personnel, operations themselves, transport costs, 

recycling costs, etc). Thus, more detailed information should be obtained during the next step 

of the investigation. On this occasion, it will also be interesting to study the zero-sum data 

probably corresponded at some volunteer management actions. 

Conclusion and the future 

Based on results from our preliminary study, the French Mediterranean region does not 

appear to be different from the whole French territory. Indeed, the presence of a large number 

of plant species has been reported but these species (except Caulerpa taxifolia) are also 

present in the country. 

Apart from slight differences in the proportions, the impacts of these species reported in 

the Mediterranean region are the same as the national level. Similarly, the main methods used 

for their management remain manual and mechanical removal. 

However, responses in the Mediterranean are scarce. Therefore, it is difficult to have a 

global vision from the 27 responses received which do not cover the entire Mediterranean 

region, and to state on the representativeness of results, including all species or the cost of 

management. 

Another investigation should be carried on in order to increase the number of responses 

and to enhance the current database with a new request for the target audience that did not 

respond in the first round, but also through disseminating the questionnaires specifically to 

new potential partners. 

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323

Afterward, a more detailed mapping analysis will be conducted to draw a broader picture 

of the species distribution and of the management actions implemented by species across the 

country. Comparing these maps may also help to identify the absence of management in 

particular cases and help identify the reason(s) for these gaps. 

Compilations and surveys have been conducted in France for over a decade, with various 

goals: first inventories (Dutartre et al., 1997), definition of status of invasion (Aboucaya, 

1999), assessment of management challenges for invasive plants (native or exotic) (Moreau & 

Dutartre, 2001) or state of the biological invasions in French Nature Reserves (Touzot et al., 

2002). The investigation reported on here has broader objectives and the data analyses of the 

information gathered during the next phase will contribute to better define the practical 

implementation of a national strategy for the management of invasive alien species. The 

network facilitating information exchange between managers and the working group BIAE 

may also contribute to disseminate information and thoughts in this field. 


The implementation of this survey on invasive alien species and their management in 

aquatic environments has prompted many reflections since February 2009. We thank all 

members of the WG BIAE who participated in the creation of the questionnaire and Katell 

Petit of International Office of Water (IOW) allowing its availability on the Internet. 

We also thank everyone who took the time to complete this survey and that allowed us to 

construct a preliminary but valuable database on the topic. 

Thanks to Sebastien Boutry for his mapping approach (Figure 1), Maud Menay for her 

comments on previous versions of the manuscript and Soizic Morin and Florian Delrue for 

their help in the English writing. 

References 

Aboucaya A (1999) Premier bilan d'une enquête nationale destinées à identifier les xénophytes invasifs sur le 

territoire français (Corse comprise). Actes du colloque " Les plantes menacées de France", Brest, 15-17 

octobre 1997. Bulletin de la Société Botanique Centre Ouest, N. S., nþ spécial 19, 463-482. 

Dutartre A, Haury J & Planty-Tabacchi AM (1997) Introduction de macrophytes aquatiques et riverains dans les 

hydrosystèmes français métropolitains. Bulletin Français sur la Pêche et la Pisciculture 344/345, 407- 

426 

Kettunen M, Genovesi P, Gollasch S, Pagad S, Starfinger U, Ten Brink P & Shine C (2008) Technical Support 

to EU Strategy on Invasive Species (IS) - Assessment of the Impacts of IS in Europe and the EU (Final 

Module Report for the European Commission). Brussels, Belgium. 

Mazaubert E (2008) Les espèces exotiques envahissantes en France : évaluation des risques en relation avec 

l'application de la Directive Cadre Européenne sur l'Eau. Bordeaux, Cemagref, Laboratoire 

d'hydrologie-environnement de l'Université Victor Segalen (Bordeaux 2), pp. 124. 

Mazaubert E & Dutartre A. (2010) "Enquête sur les espèces exotiques envahissantes en milieux aquatiques en 

métropole et leur gestion. Réalisation et première analyse des résultats (Rapport d'étape)." Rapport 

Cemagref, pp.43. 

Moreau A & Dutartre A (2000) Elaboration d'un guide de gestion des proliférations de plantes aquatiques. 

Synthèse des données d'enquête. Rapport de phase 2. Agence de l'Eau Adour Garonne. Cemagref, Unité 

de Recherche Qualité des Eaux, pp. 21 + annexes. 

Muller S & Soubeyran Y (coords.) (2010) Mieux agir contre les espèces exotiques envahissantes. Conférence 

française pour la biodiversité, 10-12 mai 2010. Note de cadrage, pp. 26. 

Pimentel D, Zuniga R & Morrison D (2005) Update on the Environmental and Economic Costs Associated with 

Alien-Invasive Species in the United States. Ecological Economics 52, 273-288. 

Richardson DM, Pysek P, Rejmánek M, Barbour MG, Panetta FD & West CJ (2000) Naturalization and Invasion 

of Alien Plants: Concepts and Definitions. Diversity and Distributions 6(2), 93-107. 

Touzot O, Dutartre A, Leveau D & Pont B (2002) Enquête sur les plantes introduites dans les réserves naturelles 

: bilan 1998. Rapport Cemagref, Réserves Naturelles de France, pp. 95. 

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324

The inventory of the alien flora of Crete (Greece) 

Costanza Dal Cin D‘Agata 1 , Melpomene Skoula 1 & Giuseppe Brundu 2 

1 Park for the Preservation of Flora and Fauna, Technical University of Crete, Michelogianni 

str. Prof. Ilias - SODY 73100, Chania, Greece 

E-mail cdagata@isc.tuc.gr; mskoula@mail.tuc.gr 

2 Department of Botany, Ecology and Geology, University of Sassari, Italy 


The island of Crete (8,729 km 2 ) lying between Greece and Libya, is the most southerly region 

of Greece and Europe. Relatively high mountains dominate the rugged landscape, the climate 

is typically Mediterranean where mean annual rainfall decreases from west to east and from 

north to south, but increases with altitude. The Mediterranean basin region has been subject to 

human intervention for millennia, so that little remains of native natural ecosystems, 

especially in the coastal area, where urban and tourism pressure are remarkable severe. Yet 

the region in general and Crete in particular, is still an important biological resource for native 

phytodiversity. 

The aim of this study, started in 2005 and presently in progress, is to carry out the first 

comprehensive inventory of the alien flora of Crete and distribution mapping of the main 

invasive alien species. Data from literature and field observations were used to develop a 

preliminary information database for the inventory that includes, so far, 272 alien taxa, 85 of 

which are naturalized, 51 are casual and 21 are considered invasive. The woody component 

comprises 142 species of trees, shrubs and sub-shrubs, woody vine and succulent. For each 

species the following information has been collected: origin, status, distribution, life form, 

phenology, habitat preferences, altitudinal range and introduction pathway. 

Mapping data has been stored in a geodatabase using GIS software, and preliminary analysis 

of the main features of the Crete alien flora is herewith presented. The most abundant and 

invasive alien species in Crete are Oxalis pes-caprae, Ailanthus altissima, Robinia 

pseudoacacia, Carpobrotus edulis, Nicotiana glauca and Ricinus communis. 

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325

Cactaceae naturalized in the Italian Mediterranean region 

Alessandro Guiggi 1 & Giuseppe Brundu 2 

1 Viale Lombardia 59, 21053 Castellanza (VA), Italy. E-mail: alex.guiggi@libero.it 

2 Department of Botany, Ecology and Geology, University of Sassari, Italy. E-mail: 

gbrundu@tin.it (Presenting author) 

The Mediterranean region has recently been interested by the introduction and invasion of 

new taxa of Cactaceae. Climate change, horticulture and deliberate introduction in the urbanwild 

interface are some the principal drivers of this phenomenon. A revision and updating of 

the previous published Catalogue of the Cactaceae naturalized in Italy is now published and 

presented here. Two new genera (Cereus, Mammillaria) and five new species (Cereus 

hildmannianus, Cylindropuntia spinosior, Mammillaria bocasana, M. elongata and M. 

polythele) are recorded for the first time and described for Italy. Noteworthy, species of the 

genus Mammillaria are recognized for the first time as naturalized in Europe. A total of 26 

taxa belonging to 8 genera have been recorded in the Mediterranean region of Italy. 

Posters 


326

Comparison of the alien vascular flora in continental islands: Sardinia (Italy) and 

Balearic Islands (Spain) 

Lina Podda 

Centro Conservazione Biodiversità (CCB), Dipartimento di Scienze Botaniche, Università 

degli Studi di Cagliari., Italia. E-mail: linap68@yahoo.it 

This paper provides a comparison of the vascular alien flora of the island of Sardinia and that 

of the Balearic Islands, both territories belonging to the Western Mediterranean biogeographic 

subregion. The study has recorded 531 exotic taxa in Sardinia (18.8% of the total flora) while 

360 (19%) were recorded in the Balearic Islands; 10 are new to Sardinia (3 for Italy) and 29 

are new for the Balearic Islands. The alien flora of Sardinia is included in 99 families; 

Fabaceae is the richest (49 taxa), followed by Poaceae (33) and Asteraceae (31) while in the 

Balearic Islands the alien flora is included in 90 families, with a predominance of Fabaceae 

(32), Asteraceae (31) and Poaceae (27). The comparison of the biological spectrum reveals 

that in Sardinia phanerophytes are the most represented, while therophytes are the most 

represented in the Balearic Islands. A detailed analysis shows that many of the exotic taxa 

(246) are shared by both territories with a clear dominance of neophytes rather than 

archaeophytes. A study of the geographical origin shows supremacy of the American element 

over the Mediterranean. The most occupied habitats are the semi-natural, agricultural and 

synanthropic for both territories, but for invasive plants, coastal habitats in Sardinia and 

wetlands in the Balearic Islands are the most sensitive. An important part of the work deals 

with the causes of fragility and low resilience of the different habitats. Further analyses have 

been undertaken to compare the densities of exotic species per area unit between Sardinia, the 

Balearic Islands and other continental and oceanic islands. 

Posters 


327

Is it the analogue nature of species which enables their successful invasion in woodland 

and coastal ecosystems of the southwest Australian Mediterranean biodiversity hotspot? 

Judith L. Fisher 1 , D Merritt 2 & K Dixon 

1, 2 

1 School of Plant Biology University of Western Australia / Fisher Research, PO Box 169, 

Floreat, Perth, Western Australia 6014, Australia. 

E-mail: ecologist@waanthropologist.com (Presenting author) 

2 Science Division Botanic Gardens and Parks Authority, Perth Western Australia 

An analogue species will be defined as an invasive alien species which mimics, to some 

extent the resident native species. The potential causes for the successful invasion of two 

analogue species, in different ecosystems i.e. woodland and coastal in the Mediterranean 

biodiversity hotspot of southwestern Australia will be investigated. Investigations have been 

conducted between the resident woodland species Austrostipa flavescens and the invasive 

Ehrharta calycina and the coastal Acacia rostellifera with the invasive Retama raetam. All 

native and invasive species are perennial, a trait of 75% of the resident native species. A 

comparison of seed biology traits between the analogue and native species has been made. We 

will provide preliminary data to determine if in fact it is the analogue nature, which has 

enabled them to establish in their new Mediterranean environment, with the differences in 

seed production and germination enabling them to be come invasive. 

Posters 


328

Alien plants in cotton fields and their impact on Flora in Turkey 

İlhan Üremiş 1 , Bekir Bükün 2 , Hüseyin Zengin 3 , Ayşe Yazlik 4 , Ahmet Uludağ 3 

1 

Univ. of Mustafa Kemal, Fac. of Agriculture, Dep. of Plant Protection, Hatay/Turkey 

E-mail: iuremis@yahoo.com 

2 

Univ. of Harran, Fac. of Agriculture, Dep. of Plant Protection, Sanliurfa/Turkey 

3 

Univ. of Igdir, Fac. of Agriculture, Dep. of Plant Protection, Igdir/Turkey 

4 

Atatürk Central Horticultural Research Institute, Yalova/Turkey 

Cotton is one of the most important crops in Turkey. Weeds are among the factors which 

interfere with cotton production. Some alien plants such as Amaranthus spp., Conyza spp, and 

Physalis spp. as well as native ones such as Sorghum halepense create problems in cotton 

fields. In addition these weeds are a problem in the other summer crops and orchards. Turkey 

is like a small continent for biodiversity as it has three bio-geographic zones (Europe-Siberia, 

Mediterranean and Irano Turanian) and transitions, and it also serves as a bridge among 

continents with big variations in climate and geographic features within a short time span 

which helps Turkey to be an important source of biodiversity. The flora of Turkey has more 

than 10 000 species of which 1/3 of them are endangered. Turkey is also a main source of 

genetic material and species richness for the whole world. Invasive species are a main threat 

to the biodiversity. There are no works on invasive species in Turkey. 

In this presentation we will use Physalis species which were recently introduced to our 

country and cause major problems in the fields. Only one Physalis species was listed in the 

flora of Turkey (P. alkekengi). Previous surveys performed in cotton fields did not report this 

species. However, surveys after 1990 showed that P. angulata, P. philedalphica var. 

immaculata ve P. lanceifolia are most abundant and widespread species in cotton fields. This 

study will focus on Phyaslis species to show invasive alien plants are a problem in arable 

areas explaining possible introduction/spread ways and possible measures. 

Posters 


329

Some Invasive Weeds in Turkey: Diplachnea fusca, Chondrilla juncea, Bromus spp. 

Mehmet Demirci 1 , , Ilhan Kaya 2 , H. Aykul 2 , Süleyman Türkseven 3 , Yıldız Nemli 3 

1 

Agrobest group, Izmir, Turkey 

2 

Yuzuncu Yil University, Agriculture Faculty, Plant Protection Department, 65080 Van, 

Turkey 

E-mail: ilhank@yyu.edu.tr (Presenting author) 

3 

Ege University, Agriculture Faculty, Plant Protection Department, Izmir, Turkey 

Chondrilla juncea L. grows naturally in the edges of fields and gardens in Turkey and in 

many European Countries. However, this plant has been known as invasive weed in Australia 

and has been causing serious problem since 1970 in wheat fields. Puccinia chondirilla, which 

is the natural enemy of C. Juncea, is widespread in Turkey and European Countries. The 

introduction of the P. chondirilla to Australia allowed an efficient biological control of C. 

Juncea. Biological control has been made successfully since its introduction. The aquatic 

plant Diphlachne fusca (L.) P. Beauv. was introduced into Turkey in the year 2003 and has 

been recorded as invasive in rice fields. It is spreading every year. There is no record of its 

presence in the Flora of Turkey dated 1975. The genuses of Avena, Phalaris, Alopecurus and 

Lolium have always been considered the most important monocotyledon weeds in wheat 

fields in Turkey. In recent years, Bromus spp. grown at the edges of the fields has begun 

causing damage in wheat fields. Bromus tectorum L. and Bromus japonicus Thunb. were 

found as two important weeds species. These two species have been reported as invasive 

plants. For the control of these invasive plants the sulfosulfuron, proxycarbazonsodium+mezosulfuron 

methyl-sodium herbicides have been recently preferred. The excessive 

weed control practices damaging the natural flora and weed transmission between countries 

have resulted in the adaptation of new weeds to the new areas and subsequently weed 

invasion of fields. 

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330

Some Important Invasive Plants Belonging to the Asteraceae Family in Turkey 

Ilhan Kaya, Işık Tepe, Reyyan Yergin 

Yuzuncu Yil University, Agriculture Faculty, Plant Protection Department, 65080 Turkey/Van 

E-mail: ilhank@yyu.edu.tr (Presenting author) 

In this study, the origins, introductions, infestations and problems caused species belonging to 

the Centaurea, Cirsium and Onopordum genera (Asteracea family) are discussed. Centaurea 

diffusa Lam. (diffuse knapweed), Centaurea solstitialis L. (yellow starthistle), Cirsium 

arvense (L.) Scop. (Canada thistle) and Onopordum acanthium L. (cotton thistle) are 

important invasive weeds for Turkey. These species originate from Europe and spread from 

this origin to other countries. C. diffusa is widespread in the Western part of North America, 

the Balkans, Ukraine, Russia. In Turkey, the species is generally seen in the Marmara Region. 

In USA, it is the main problem in alfalfa. This plant is mainly seen on roadsides, pastures and 

uncultivated land. C. solstitialis is introduced to Africa, Asia, West and Central America from 

Europe. It is found in almost all regions of our country and causes damage in meadow-pasture 

and uncultivated land. C. arvense is seen in the Caucasus, Iran, Afghanistan, North Asia, 

North America and in the whole of Turkey. This plant can cause yield reduction in cereals, 

maize, sugar beet, potatoes, sunflowers, legumes, vegetables gardens, fruit orchards, 

meadows, pastures and forage crops. O. acanthium was spread to Central Asia and North 

America from Europe. In Turkey, it is seen in Eastern, Northern and Southern Anatolia, 

mainly in roadsides and cultivated areas. These plants, belonging to the Asteraceae family, 

have spread between countries and have been creating important problems in the introduction 

areas. These plants were originally introduced from Europe and gained considerable attention 

as invasive weeds of agricultural and non-agricultural areas. 

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331

Some Invasive Obligate Parasitic Plants: Cuscuta spp., Orobanche spp., Phelipanche spp. 

Yıldız Nemli 1 , Reyyan Yergin 2 , Şeyma Tamer 1 , Peyman Molaei 1 , Ahmet Uludag 3 , 

Süleyman Türkseven 1 

1 Ege University, Faculty of Agriculture, Department of Plant Protection, 35100, Izmir, 

Turkey 

2 Yuzuncu Yil University, Faculty of Agriculture, Department of Plant Protection, 65080, Van, 

Turkey 

3 Igdır University, Faculty of Agriculture, Department of Plant Protection,76000, Igdır, 

Turkey 

E-mails: yildiz.nemli@ege.edu.tr, reyyanyergin@yyu.edu.tr, seyma85tamer@hotmail.com, 

molaei.p59@gmail.com, ahuludag@yahoo.com, suleyman.turkseven@ege.edu.tr 

Introduction 

Cuscuta, Orobanche and Phelipanche spp. are important parasitic plant 

genera in Turkey as well as worldwide. Two cuscuta species one native to 

the old world, C. approximata, and the other native to the new world, C. 

campestris, became problematic in both worlds due to their invasiveness. 

Orobanche spp. and Phelipanche spp. parasitize many crops such as tomato, 

tobacco, sunflower, lentil and faba bean in Mediterranean countries which 

represent their native range. They are known as invasive and problematic in 

the USA. It is concluded that parasitic plants are invasive plants can create 

problems in introduced areas in their native places. 

Turkey has a very rich and diverse flora with 8707 vascular plants and 85 non vascular 

plants reported (Davis, 1988). Endemic plants represent approximately 30% of the flora while 

many other plants are clasified as rare or endangered. Few species are documented as alien. 

Parasitic plants also contribute to the richness of Turkey‘s flora. Parasitic plant species 

from the Cuscutaceae, Loranthaceae, Orobanchaceae, Rafflesiaceae, Santalaceae, 

Scrophulariaceae families have been recorded in the flora of Turkey (Uludag & Nemli, 

2009). Parasitic plants have been detected in both agricultural and non-agricultural areas. The 

most economically important parasitic plants in Turkey are broomrapes (Orobanche spp. and 

Phelipanche spp.) followed by dodders (Cuscuta spp.). Some of these species are introduced, 

but most of them are native to the Mediterranean basin. 

This presentation discusses broomrapes‘ and dodders‘ origins, introductions, infestations 

and problems caused, illustrated with some examples. 

Dodders (Cuscuta spp.) 

Dodders (Cuscuta spp.) are holoparasitic plants belonging to Cuscutaceae which parasite 

stems and branches of their hosts. Approximately 120 dodder species have been recorded all 

over the world (Yuncker, 1932). There are 15 dodder species in Turkey (Plitmann, 1978; 

Nemli, 1978). Economicaly important dodder species are C. campestris Yunck, C. 

approximata Bab., and C. monogyna Vahl. (Table 1). These three species have different 

invasion patterns as explained below. 

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332

Table 1 - The main dodders species and their host in Turkey (Nemli, 1978, Nemli, 1986) 

Species Host 

C. campestris Yunck. Capsicum annuum L., Medicago sativa L., Allium sativum L., 

Daucus carota L., Pimpinella anisum L., Carum carvi L. 

C.ampproximata Bab. Medicago sativa L. 

C. monogyna Vahl. Vitis vinifera L., Rubus spp., Rhus coriaria L., Paliurus spinacristi 

Mill., Quercus coccifera L. 

C. campestris, native to the USA, is distributed all over the world. It is thought that C. 

campestris was introduced in Turkey in 1925 via seeds imported. It infests over 40 plants 

species that are wild or domesticated in all regions of Turkey (Nemli, 1978). 

C. approximata is native to the old world, and had been introduced into North America. It 

isa ―noxious weed‖ in many countries (Yunker, 1932). It attacks lucerne and is called alfa alfa 

dodder. In many case, C. approximata infests lucerne with C. campestris. 

C. monogyna is native to the old world, from France, North Africa, Europe, Central Asia to 

Aganistan and Persia including Turkey. Its hosts are woody plants. It is found in large areas 

on Vitis vinifera around the Cappadocia (Ürgüp). Its hosts in Turkey are Rhus coriaria, Styrax 

officinalis, Pistacia vera, Rubus sp., Rosa sp., Quercus coccifera, Crataegus sp., Poliurus 

spina-cristi (Nemli, 1978). It is not being found in North America. It spreads around his 

native area and not introduced to other continent. 

Broomrapes (Orobanche spp. and Phelipanche spp.) 

Parasitic plants from the genera Orobanche and Phelipanche are called broomrapes (Joel, 

2009). In most of the literature these two genera are considered as one genus as Orobanche 

(Gilli, 1982 ). Although we recognize separated genera as Joel (2009) indicates, we will use 

Orobanche only because we will follow Flora of Turkey (Gilli, 1982) in this paper. 

Traditional morpholgy is of limited value in Orobanche, because of reduced plant body 

(Musellman, 1994). Traditional plant anatomy, polen morphology, seed-microstructure 

caracteres are necessary to clarify the identity of the plants. 

Broomrapes are holoparasitic plants and attack roots of their host. There are 35 broomrape 

species in Turkey (Gilli, 1982). Four broomrape species are widespread and serious problem 

in agricultural crops (Table 2). Those species are O. crenata Forsk., O. cernua Loefl., O. 

ramosa L., and O. aegyptiaca Pers.. 

Broomrapes are native to the Mediterranean region (i.e., North Africa, the Middle East, 

and southern Europe), and Western Asia, where they cause significant crop damage (Parker & 

Riches, 1993). Broomrape species have spread in many parts of the world. According to 

Musselman (1994) the first serious infestation of O. ramosa in the USA was in Kentucky 

(German, 1903). In the same time, it has spread to California and then to Texas in 1982. The 

distribution of Orobanche species extended to central Europe, which were first recorded in 

Serbia in 1951 (Mašireviš & Mediš-Pap, 2009). 

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333

Table 2 - Major species and some of their hosts ( Parker, 1986; Nemli et al., 2009 

Species Host 

O. crenata Forsk. Vicia faba L., 

Pisum sativum L. 

Cicer arietinum L. 

Lens culinaris Medick. 

O. cernua Loefl. 

Helianthus annuus L. 

(Syn: O.cumana Waller) 

O. ramosa L. / O. aegyptiaca Pers Lycopersicon esculentum Mill. Nicotiana tabacum L. 

Solanum melongena L. 

Solanum tuberosum L. 

Lens culinaris Medick. 

Conclusions 

In this paper, it has been shown that parasitic plants also can show invasive characters. 

Broomrape species, which are native to Mediterranean areas, have reached central Europe. 

Their further spread might be expected due to climate change. Two dodder species one native 

to the old world, C. approximata, and the other native to the new world, C. campestris, 

became problematic in both worlds due to their invasiveness. Their occurrence in lucerne 

fields in both areas might help to figure out their introduction pathways: seed import/export, 

which highlights the importance of quarantine measures to prevent the spread of invasive 

plants. 

References 

Davis PH (1988) Flora of Turkey and East Aegean Islands. Vol:10, Edinburg University Press. 

Gilli A (1982) Orobanche L. In: Flora of Turkey and East Aegean Islands (Ed. Davis PH), Vol. 7 pp. 3-23, 

Edinburg University Press. 

Joel D (2009) Taxonomic and evolutionary justifications for considering Phelipanche as a separate genus. In: 

Proceedings 10th World Congress on Parasitic Plants, 8-12 June 2009, Kusadasi, Turkey (Ed. Rubiales 

D, Westwood J & Uludag A). pp. 15. 

Mašireviš S & Mediš-Pap S (2009) Broomrape in Serbia from its occurrence till today. Helia 32, 91-100. 

Musselman LJ (1994) Taxonomy and Spread of Orobanche. In: Biology and Management of Orobanche, Proc. 

Of the Third International Workshop on Orobanche and related Striga research (Ed. Pieterse AH, 

Verkleij JAC & ter Borg SJ). Pp. 27-35. Royal tropical Institute. Amsterdam, The Netherlands,. 

Nemli Y (1986) Anadolu‘da kültür alanlarında bulunan küsküt türleri (Cuscuta spp.); yayılışları ve konukçuları 

üzerinde araştırmalar. E.Ü.Z.F. Dergisi 23 (3), 11-21. (in Turkish). 

Nemli Y (1978) Çiçekli Parazit Bitkilerden Cuscuta L.‘nin Anadolu Türleri Üzerinde Morfolojik ve Sistematik 

Araştırmalar. Doktora Tezi, Ege University (in Turkish). 

Nemli Y, Uludag A, Türkseven S, Demirkan H & Kaçan K (2009) Research on broomrape control in tomato 

fields in western Turkey. In: Proceedings 10th World Congress on Parasitic Plants, 8-12 June 2009, 

Kusadasi, Turkey (Ed. Rubiales D, Westwood J & Uludag A). pp. 90. 

Parker C (1986) Scope of agronomic problems caused by Orobanche species. Proc. Biology and Control of 

Orobanche. (Ed. Ter Borg SJ). pp:11-17. LH/VPO, Wageningen, The Netherlands. 

Parker C & Riches CR (1993) Parasitic Weeds of the World: Biology and Control. CAB International 

Plitmann U (1978) Cuscuta L. In: Flora of Turkey and East Aegean Islands (Ed. Davis PH), Vol. 6 pp. 222-237, 

Edinburg University Press. 

Uludag A, Nemli Y (2009) Parasitic flowering plants in Turkey. In: Proceedings 10th World Congress on 

Parasitic Plants, 8-12 June 2009, Kusadasi, Turkey (Ed.Rubiales D, Westwood J & Uludag A). pp. 57. 

Yuncker TG (1932) The Genus Cuscuta. Memoirs of the Torrey Botanical Club, Vol. 18, 113-331. 

Posters 


334

Some invasive weeds in cereal areas of Northern Cyprus: Oxalis pes-caprae and 

Gladiolus italicus 

A. Göksu 1 , Y.Nemli 2 , K. Vurana 1 , B.Gökhan 1 , S. Türkseven 2 , M. Demirci 3 , A. Erk 1 , E. 

Hakel 1 

1 Ministry of Agriculture of Turkish Republic of Northern Cyprus 

2 Ege University, Izmir, Turkey 

3 Agro Best Group, Izmir, Turkey 

There are 69.2 thousands hectares of agricultural area of which 89% is under dryland farming, 

in the Turkish Republic of Northern Cyprus. Cereals cover 60% of the agricultural area. 

Barley is the main cereal, representing 92% of the production. Two common weeds from 

barley fields will be discussed in this presentation: Gladiolus italicus and Oxalis pes-caprae. 

G. italicus is a perennial plant of Eurasian origin. Its pink blossom, which occurs in February 

and March, is its most noticeable character. The plant can reach up to 1 m high. It is common 

in barley fields in Carpaea Region which is one of the rainy parts of Cyprus. Its Turkish name 

is ―arpa otu‖ which means literally ―barley‘s weed‖. 

O. pes-caprae is a South African geophyte which spreads vegetatively by bulbils and 

underground shoots, and easily colonizes many areas. It has been introduced into many 

Mediterranean and temperate regions of the world. It has spread in many islands. Similarly to 

G. italicus, it is common in the Carpea region. It does not let other plants grow around it and 

invades a whole field. It is observed that another common weed of the region, Sinapis alba 

cannot spread in the same field infested by O. pes-carpae. 

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335

Validation and use of the Australian Weed Risk Assessment in Mediterranean Italy 

Roberto Crosti 1 , Carmela Cascone 2 & Salvatore Cipollaro 2 

1 

c/o ISPRA Dipartimento Difesa della Natura Tutela biodiversità Via Curtatone 3 - 00185 

Roma, Italy 

E-mail: robertocrosti@libero.it 

2 

ISPRA Dipartimento Difesa della Natura-Uso Sostenibile Risorse Naturali, Rome, Italy 

A biological invasion is always an irreversible process which often leads to ecological and 

economic harm. The capacity to pre-screen potential invasiveness of plant species is, 

consequently, important for the conservation and management of natural habitats, especially 

within agro-ecosystems. In this type of anthropogenic manipulated ecosystem, many factors 

increase the creation of newly available niches. As a consequence, the presence and 

establishment of invasive species with the potential to spread and cause harm, or constrain 

elements of semi-natural habitat or vegetation remnants, may increase. The invasiveness of 

weedy germplasm may also be accelerated by the propagule pressure of cultivated species that 

are able to escape from fields through crop movement or on livestock. The future use of 

agricultural land for widespread and intensive cultivation of biofuel crops for energy 

production increases the need for a pre-entry screening tool both for species that are new to 

the Italian cropping system and for the management of existing weedy species. This study 

aimed to assess the effectiveness of adapting the Australian and New Zealand Weed Risk 

Assessment (WRA) to the geographic, climatic and weed management context of Italy. We 

evaluated the performance of the adapted WRA on several alien plant species of known 

invasiveness in Mediterranean Central Italy. WRA score results were compared with a priori 

independent opinions of botanists with field experience in the evaluated region. The 

assessment procedure correctly identified 93% of invasive species and 75% of non-invasive 

species. Further evaluation was needed for 20% of the tested species and was conducted 

through a secondary screening. Throughout the whole process, only one (5%) of the 

investigated species could not be assessed. The results of the Receiver Operating 

Characteristic analysis, the consistency of the outcomes with those found in other WRA 

studies, the Chi Square testing categories and the high correlation between the a priori and 

WRA score corroborated the predictive accuracy of the WRA for determining invasive from 

non-invasive species. This confirmed the effectiveness of the screening process and an 

assessment was subsequently carried out on proposed biofuel species detecting some potential 

invaders. The WRA can thus be used to assess the introduction of new cropping systems and 

for weed management. 

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A proposal for a cooperation program on modeling the spread of invasive weeds 

Guillaume Fried 1 , Anwar Al Mouemar 2 & Henry Darmency 3 

1 Laboratoire National de la Protection des Végétaux, Station de Montpellier, CBGP, 

Campus International de Baillarguet, CS 30016, 34988 Montferrier-sur-Lez Cedex, France. 


2 Faculty of Agronomy, Damas, Syria 

3 INRA, Dijon, France 

Evidence of northern spread of Solanum eleagnifolium and Echhornia crassipes in Syria is 

certainly a marker of the global warming effect. A few casual occurrences are also noticed in 

the Mediterranean area in France. It is likely that the distribution of these weeds will continue 

to progress northward. Since there are few efficient control methods, preventive actions where 

the weeds are not yet established seems to be the best way to manage the threat. 

Consequently, monitoring the habitats which are prone to the entry and establishment of these 

weeds, as well as sensitive habitats with threatened species or plant communities, is the only 

but urgent measure that countries of the northern border of the Mediterranean Sea must set up. 

Ecological and biological characteristics drawn from the experience and knowledge of 

countries where the invasive weeds are already present and continue to occupy new areas can 

provide suitable data to model the favorable habitats and the endangered areas. More precise 

measurements of certain key aspects of the life cycle should improve current available 

models. Reciprocally, such predictive models can provide new insights into the possible 

management of habitats allowing better control of the invasive weeds. The eco-climatic 

conditions in Syria and in the South of France fit the described situation and provide the 

opportunity to launch a bilateral cooperative program on this topic. We invite all colleagues 

from any countries to join us and to propose a more global program. 

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Impact of Humulus japonicus on riparian communities in the south of France 

Guillaume Fried 

Laboratoire National de la Protection des Végétaux, Station de Montpellier, CBGP, Campus 

International de Baillarguet, CS 30016, 34988 Montferrier-sur-Lez Cedex, France. 


Japanese hop (Humulus japonicus Sieb. et Zucc., syn. H. scandens Lour. Merrill) is an annual 

fast-growing vine, native to deciduous forests of East Asia (Japan, China, Korea, Russian Far 

East). It was introduced to Europe in 1886 for ornamental purposes. So far, its naturalisation 

was only known from Hungary, North Italy and Slovenia. In France, the plant was observed 

for the first time in 2004 in a riparian habitat near the Gard river (south of France). 

In Hungary, dense stands are reported to endanger the vegetation along rivers. Since precise 

data on impacts were lacking, vegetation in invaded and uninvaded plots with similar site 

conditions was sampled. In stands of H. japonicus mean species richness per m² only reached 

3.63 (range: 0-6). In comparison, non-invaded neighbouring areas contained an average of 

9.33 species per m² (range: 5-14). The most frequent species associated with H. japonicus 

were Chenopodium album, Galium aparine and Rumex obtusifolius. 

We observed a high competitive ability of H. japonicus: even tall species such as Sorghum 

halepense or Arundo donax were bent under the load of its thick, heavy and shady mesh. Only 

two species: Parthenocissus inserta and Cucubalus baccifer, with a similar biological life 

form (climbing stems) were observed at high coverage with H. japonicus. 

If species richness is reduced by 60%, the invaded communities do not present a high floristic 

interest as they are mostly composed of ruderal and nitrophilous species (Atriplex prostrata, 

Torilis arvensis), or other invasive species (Ambrosia artemisiifolia, Artemisia verlotiorum, 

Helianthus tuberosus). Moreover, H. japonicus forms an important litter that can modify the 

substrate for many years. The potential impact of this species on other riparian communities 

should therefore not be overlooked. Finally, it should be remembered that the pollen of H. 

japonicus is allergenic and could provoke health problems. 

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Allélopathie chez Oxalis pes-caprae comme mécanisme potentiel d’invasion des céréales 

d’automne 

M Bouhache, A Taleb & A Gharmmate 

Institut Agronomique et Vétérinaire Hassan II, B.P. 6202, Rabat –Instituts, Maroc 

E-mail : m.bouhache@gmail.com & a.taleb@iav.ac.ma 

Introduction 

Originaire d‘Afrique du Sud, Oxalis pes-caprae L. (= O. cernua Thumb.) 

(oxalide en français) est une adventice envahissante largement distribuée 

dans toutes les régions à climat méditerranéen. C‘est une espèce 

dicotylédone bulbeuse et rhizomateuse qui se reproduit végétativement par 

bulbilles. Au Maroc, cette espèce a été introduite au début du 19 ème cycle. 

Elle a été considérée comme espèce naturalisée et rudérale. Actuellement, 

elle infeste les écosystèmes agricoles. Cette étude a été conduite dans le but 

d‘étudier les effets allélopathiques des extraits aqueux d‘O. pes-caprae sur 

la germination et la croissance des céréales d‘automne (blé tendre, blé dur et 

orge). Aux stades végétatif et floraison de l‘oxalide, les extraits aqueux des 

parties aérienne et racinaire à l‘état frais et sec ont réduit significativement 

la germination des semences (mises dans des boites de Pétri) des trois 

céréales. En outre, ces extraits ont également réduit la longueur et la 

biomasse des racines et des coléoptiles des céréales. L‘effet allèlopathique 

dépend de l‘espèce de céréale, mais aussi de l‘organe et du stade de 

l‘oxalide pour l‘extraction des substances allélopathiques. L‘effet inhibiteur 

des extraits s‘est révélé très prononcé à la concentration la plus élevée 

(extrait non dilué). 

L'oxalide pied de chèvre (Oxalis pes-caprae L.) est une adventice vivace, dicotylédone, 

appartenant à la famille des Oxalidaceae, originaire d‘Afrique du Sud et qui a envahi 

différentes régions du monde à climat méditerranéen. Son introduction au Maroc est plus 

récente puisqu‘elle est présente dans plusieurs régions du Maroc depuis le début du siècle ? 

(Jahandiez & Maire, 1931). 

Au début de son introduction, l‘oxalide se comportait comme une espèce rudérale et était 

cantonnée le long des routes, des clôtures ou haies, au voisinage des bâtiments et le long des 

cours d‘eau. Actuellement, son aire d‘invasion s‘est élargie et l‘espèce a gagné les jardins 

privés et publics, les paysages urbains, les vergers et les cultures. Le niveau d'infestation de 

cette espèce dans les milieux cultivés a ainsi beaucoup augmenté. En culture des céréales, une 

densité de 135 pieds/m 2 d‘oxalide a été notée dans la région de la Chaouia (Rsaissi, 1994). 

L‘oxalide est ainsi considérée comme l'une des espèces problématiques des céréales dans 

plusieurs régions du Maroc (Tanji, 1988 ; Tahri, 1993 ; Rsaissi, 1994). Un tel niveau 

d‘infestation cause une perte de rendement en grain des céréales d‘automne de 35 à 42 % 

(Rsaissi, 1994). 

Sur la base des processus écologiques, l‘épuisement des ressources (compétition, 

utilisation des ressources et allélopathie) est l‘une des trois catégories de mécanismes 

d‘invasion biologique utilisées par les plantes (Ren & Zhang, 2009). L'allélopathie consiste à 

émettre ou à libérer des substances organiques par divers organes d'une plante (vivante ou 

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morte) dans un milieu et ces substances peuvent inhiber ou stimuler la croissance des plantes 

avoisinantes ou succédantes. En d'autres termes, il s'agit de l'interaction biochimique entre 

deux plantes (Rice, 1984). En effet, Qasem (1995a) avait démontré que les extraits aqueux ou 

la matière sèche des parties aériennes au sol de plusieurs espèces adventices, 

accompagnatrices du blé en Jordanie, ont un effet allèlopathique sur la germination et la 

croissance de cette céréale. 

En absence d'investigation sur le phénomène d'allèlopathie des mauvaises herbes des 

céréales au Maroc, cette étude a pour objectif de vérifier l'existence d'un tel phénomène chez 

l'oxalide afin de comprendre sa recrudescence dans ces cultures. 

Matériel et méthodes 

1. Origine du matériel végétal 

Les lots de semences des céréales non traitées (blé dur, blé tendre et orge) ont été offerts 

par le Service de Certification des Semences et des Plants (D.P.V.C.T.R.F.). Trois variétés de 

chaque espèce ont été retenues: Marzak, Karim et Oum Rabia pour le blé dur ; Merchouch, 

Kanz et Achtar pour le blé tendre et enfin Tamellalt, Tiddas et Tissa pour l'orge. 

L'oxalide (Oxalis pes-caprae L.) a été récoltée à l'état frais à partir d'une parcelle infestée 

naturellement à l'Institut Agronomique et Vétérinaire Hassan II à Rabat, aux stades végétatif 

et floraison. 

2. Préparation des extraits de l'oxalide 

Une quantité de 150g de chaque partie de l'oxalide fraîche a été lavée avec de l'eau potable. 

Seules les racines ont été mises dans une solution de l'hypochlorite de sodium à 10% (v/v) 

pendant 5 mn et nettoyées avec de l'eau potable puis avec de l'eau distillée. Les deux parties 

ont été broyées séparément dans un mixeur pendant 5 mn dans un litre d'eau distillée. Le 

mélange a été laissé à décanter pendant une demi-heure. Le broyât est filtré au moyen d'un 

tamis de 0,75 mm de maille dans la première étape et dans une deuxième à travers le papier 

Wattman nþ l. 

La même procédure a été suivie pour les échantillons secs. Toutefois, les quantités prises 

ont été de 17,2 et 16,4 g respectivement de la partie aérienne et souterraine. Ces quantités 

représentent l'équivalent de 150 g de leurs poids frais. L'oxalide fraiche a été séchée à la 

température de 80þC pendant 48h. 

3. Mise en germination des semences de céréales 

Un lot de 10 semences de chaque variété des céréales a été placé sur le papier filtre dans 

des boites de Pétri (diamètre = 8,5 cm). Des volumes d'extraction de l'oxalide des parties 

aériennes et souterraines (fraîches ou sèches), ont été ajoutés à des proportions de 0, 3, 6 et 10 

ml dans chaque boite de Pétri. Le volume final a été ramené à 10 ml avec l'ajout d‘eau 

distillée, ce qui nous a permis d'obtenir les concentrations suivantes: 0, 30, 60 et 100%. Les 

boites de Pétri ont été mises à incuber pendant 10 jours à la température ambiante de 

laboratoire et à l'obscurité. Au troisième jour de mise en germination, 2 ml d'une solution à 

base de bénomyl (fongicide) à la concentration de 3 g/l ont été ajoutés dans chaque boite de 

Pétri. Ce traitement a été fait pour éviter toute contamination par des champignons. 

4. Mesures et observations 

A la fin de la durée d'incubation (10 jours), les paramètres suivants ont été mesurés: 

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- pourcentage de germination (%), 

- longueur moyenne du coléoptile (cm), 

- longueur moyenne de la radicule (cm) 

- poids frais moyen du coléoptile (g), 

- poids frais moyen de la radicule (g). 

5. Analyses statistiques 

Avant de soumettre les données obtenues à l'analyse de la variance, la transformation arc 

sin de la racine carrée a été adoptée pour les pourcentages de germination. Dans les cas de la 

longueur et du poids, la transformation Log (x+l) a été utilisée après vérification de 

l'homogénéité des variances avec le test de Hartley. Pour chaque espèce de céréale, les 

résultats présentés sont les moyennes des trois variétés. 

Résultats 

L'analyse des résultats a permis de relever que les extraits aqueux de l'oxalide, aux stades 

végétatif et floraison, ont un effet allèlopathique sur la germination et la croissance des trois 

céréales étudiées. L‘importance du phénomène dépend de l‘espèce de céréale, mais aussi du 

stade, de l‘organe et de l‘état de l‘oxalide (Tableaux 1, 2, 3, 4, 5 et 6). 

Tableau 1 - Effet des extraits aqueux de l'oxalide au stade végétatif sur la germination et la 

croissance du blé dur. 

Partie de la Concen- Germina- Poids moyen (g) Longueur moyenne (cm) 

plante tration tion (%) Radicule Coléoptile Radicule Coléoptile 

Aérienne 

Fraîche 

Aérienne 

Sèche 

Racinaire 

Fraîche 

Racinaire 

Sèche 

0 85,5 a* 0,12 a 0,08 a 16,2 a 10,0 a 

30 80,0 a 0,04 b 0,06 b 3,9 b 8,6 b 

60 53,3 b 0,03 c 0,05 b 2,9 c 6,4 b 

100 37,8 b 0,01 c 0,05 b 1,5 d 3,9 c 

0 80,0 a 0,08 a 0,12 a 11,2 a 15,4 a 

30 82,9 a 0,08 a 0,12 a 10,4 a 14,4 a 

60 64,4 b 0,05 b 0,10 b 7,8 b 13,3 b 

100 55,6 b 0,04 b 0,09 b 5,7 c 11,1 c 

0 94,4 a 0,12 a 0,08 a 18,1 a 11,4 a 

30 90,0 a 0,05 b 0,08 a 7,5 b 9,4 a 

60 64,4 b 0,03 c 0,06 b 2,9 c 7,5 b 

100 45,6 c 0,02 c 0,04 b 2,4 c 7,0 b 

0 77,8 a 0,10 a 0,13 a 12,3 a 16,2 a 

30 77,8 a 0,07 b 0,12 b 9,7 b 14,2 a 

60 71,1 a 0,06 b 0,13 a 8,2 b 15,4 a 

100 47,8 b 0,05 b 0,10 b 6,9 c 11,6 b 

*Pour chaque partie de la plante et pour chaque état de l‘oxalide, les chiffres d‘une même 

colonne de la même lettre ne sont pas différents significativement selon le test de Student- 

Newman-Keuls à p=0,05. 

1. Stade végétatif 

En général, le pourcentage d'inhibition de la germination du blé dur, du blé tendre et de 

l'orge tend à augmenter avec la concentration de l'extrait d‘oxalide. A la concentration de 

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100%, la germination a été réduite de 30,4 à 68,6% selon les espèces. En général, l'effet 

allèlopathique est plus important avec les extraits des parties fraîches de l'oxalide. De même, 

la partie aérienne fraîche a tendance à avoir plus d'effet que la partie racinaire. Une fois 

séchée, la partie racinaire a tendance à inhiber la germination des semences de céréales plus 

que la partie aérienne. A la concentration de 30%, l'effet négatif des extraits aqueux n'est pas 

significatif ou a été stimulateur de la germination en comparaison avec le témoin. En général, 

la germination de l'orge est plus affectée que celle des blés (Tableaux 1, 2 et 3). 

La présence des extraits aqueux de l'oxalide dans le milieu de germination a un effet 

inhibiteur sur le poids et la longueur de la radicule et du coléoptile des plantules des trois 

céréales tableaux 1, 2 et 3). Le poids et la longueur de la radicule ont été plus touchés que 

ceux du coléoptile. Ainsi, les pourcentages de réduction du poids de la radicule et du 

coléoptile ont varié de 44 à 92% et de 0 à 54,5%, respectivement. Les longueurs de la radicule 

et du coléoptile ont été réduites de 42 à 92% et de 5,2 à 61%, respectivement. En général, les 

extraits aqueux des parties fraîches ont plus d'effet sur la radicule que ceux des parties sèches. 

Aux concentrations intermédiaires (30 et 60%), la croissance du coléoptile n'est pas affectée 

négativement ou est stimulée en comparaison avec le témoin. La croissance de la radicule du 

blé dur est plus inhibée par les extraits que celle du blé tendre et de l'orge (Tableaux 1, 2 et 3). 


croissance du blé tendre 



Aérienne 

Fraîche 

Aérienne 

Sèche 

Racinaire 

Fraîche 

Racinaire 

Sèche 

0 98,9 a* 0,09 a 0,07 a 13,3 a 8,4 a 

30 93,3 b 0,06 b 0,07 a 6,5 b 8,6 a 

60 70,0 c 0,02 c 0,05 b 2,4 c 5,9 b 

100 47,8 d 0,01 c 0,05 b 1,4 c 5,0 b 

0 82,3 a 0,09 a 0,11 b 11,6 a 13,1 a 

30 71,1 a 0,07 ab 0,12 a 10,6 ab 13,5 a 

60 66,6 a 0,06 b 0,10 b 8,4 b 11,9 a 

100 55,8 a 0,03 c 0,06 b 3,8 c 8,1 b 

0 97,8 a 0,09 a 0,07 b 13,2 a 9,8 b 

30 86,7 b 0,07 b 0,09 a 9,1 b 12,6 a 

60 76,7 b 0,05 c 0,08 a 5,0 c 11,6 a 

100 52,2 c 0,02 d 0,05 b 2,1 d 7,2 b 

0 85,6 a 0,09 a 0,09 b 12,0 a 11,5 a 

30 83,3 a 0,09 a 0,13 a 10,7 b 13,0 a 

60 68,9 a 0,06 b 0,11 ab 7,5 c 12,3 a 

100 57,8 b 0,05 b 0,09 b 6,0 d 10,9 a 




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croissance de l'orge 



Aérienne 

Fraîche 

Aérienne 

Sèche 

Racinaire 

Fraîche 

Racinaire 

Sèche 

0 92,2 a* 0,12 a 0,11 a 13,2 a 10,5 a 

30 90,0 a 0,07 b 0,08 ab 5,9 b 8,6 ab 

60 76,7 b 0,04 c 0,09 b 3,3 c 7,2 ab 

100 28,9 c 0,02 c 0,05 b 1,1 d 5,6 b 

0 66,7 a 0,09 a 0,16 a 10,0 a 15,3 a 

30 72,2 a 0,07 ab 0,16 a 8,4 b 16,8 a 

60 60,0 b 0,07 ab 0,16 a 6,8 bc 14,9 a 

100 42,2 b 0,0‘ b 0,13 a 5,8 c 13,1 a 

0 95,6 a 0,11 a 0,11 a 14,2 a 11,9 a 

30 93,3 a 0,07 b 0,12 a 8,1 b 12,7 a 

60 74,4 b 0,05 b 0,09 b 4,4 c 9,8 a 

100 44,4 c 0,03 c 0,07 b 2,0 d 6,9 b 

0 76,7 a 0,10 a 0,16 a 10,1 a 15,6 ab 

30 77,8 a 0,07 b 0,17 a 8,5 a 16,3 a 

60 65,6 a 0,05 bc 0,14 ab 5,6 b 14,8 ab 

100 38,9 b 0,04 c 0,13 b 4,3 b 13,3 b 




2. Stade floraison 

L'inhibition de la germination par les extraits aqueux de l'oxalide dépend de l'espèce de 

céréales et de la concentration de l'extrait. La germination du blé tendre est moins sensible 

aux extraits aqueux en comparaison avec le blé dur et l'orge. Plus la concentration de l'extrait 

est grande plus le pourcentage d'inhibition est important. A la concentration de 100%, la 

germination a été réduite de 5,8 à 55,9%. Contrairement aux parties souterraines de l'oxalide, 

les parties fraîches aériennes ont plus d'effet que les parties aériennes sèches. De même, les 

extraits aqueux de la partie aérienne de l'oxalide ont plus d'effet allélopathique que la partie 

racinaire (Tableaux 4, 5 et 6). 

La croissance en termes de poids et de longueur de la radicule et du coléoptile a été affectée 

par l'ajout des extraits aqueux de l'oxalide dans le milieu de germination. A ce stade, le poids 

et la longueur de la radicule des céréales ont été plus réduits que ceux du coléoptile. Les 

pourcentages de réduction du poids de la radicule et du coléoptile varie de 0 à 73 et de 0 à 

39%, respectivement. Par ailleurs, la longueur de la radicule et du coléoptile a été réduite de 

1,1 à 87,5% et de 0 à 47%, respectivement. Les extraits aqueux de la partie aérienne fraîche 

ont été plus nocifs que ceux de la partie aérienne sèche. Les extraits de la partie racinaire 

sèche ont beaucoup plus inhibé la croissance des céréales que ceux de la partie racinaire 

fraîche (Tableaux 4, 5 et 6). En général, un effet allélopathique négatif négligeable et/ou un 

effet stimulateur de la croissance des céréales a également été observé aux concentrations 

intermédiaires. La croissance radiculaire du blé dur est plus inhibée que celle du blé tendre et 

de l'orge par les extraits de la partie aérienne de l'oxalide, alors que la racine de l'orge est plus 

affectée par les extraits de la partie racinaire de l'oxalide que celle des blés. 

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Tableau 4 - Effet des extraits aqueux de l‘oxalide au stade floraison sur la germination et 

la croissance du blé dur 



Aérienne 

Fraîche 

Aérienne 

Sèche 

Racinaire 

Fraîche 

Racinaire 

Sèche 

0 93,3 a* 0,11 a 0,09 a 14,3 a 12,1 ab 

30 85,6 b 0,08 b 0,12 a 11,1 b 15,0 a 

60 67,8 c 0,04 c 0,06 b 4,1 c 7,5 b 

100 41,1 d 0,03 c 0,06 b 2,4 d 6,4 c 

0 72,2 a 0,08 a 0,09 a 15,0 a 11,7 a 

30 63,3 a 0,07 ab 0,10 a 10,7 b 11,1 a 

60 65,5 a 0,06 ab 0,07 b 8,7 b 10,1 a 

100 50,0 a 0,05 c 0,06 b 4,9 c 8,5 b 

0 88,9 ab 0,11 b 0,11 c 18,9 a 12,2 b 

30 94,4 a 0,13 a 0,12 b 19,0 a 16,2 a 

60 91,1 ab 0,12 ab 0,15 a 18,9 a 16,9 a 

100 82,2 b 0,11 b 0,12 b 18,4 a 15,9 a 

0 74,4 a 0,07 a 0,09 a 14,4 a 12,7 a 

30 66,7 a 0,06 a 0,09 a 8,4 b 11,3 a 

60 66,7 a 0,04 b 0,07 b 6,5 b 10,7 a 

100 56,7 a 0,03 b 0,06 b 4,9 c 10,3 a 



Newman-Keuls à p=0,05 

Discussion 

Bien que l‘oxalide soit une géophyte (vivace), elle arrive à boucler son cycle végétatif avant 

la maturation des céréales et sa partie végétative aérienne disparaît complètement du champ. 

De ce fait, seules les bulbilles persistent dans le sol et y restent vivantes pour ré-infester le 

champ la campagne agricole suivante (Ater, 2005). Les peuplements denses de cette adventice 

sont parfois la cause de pertes considérables (jusqu‘à 42%) de rendement de céréales infestées 

et d‘ intoxications du bétail (Rsaissi & Bouhache, 2005). En outre, Vilà et al. (2006) ont 

démontré expérimentalement dans quelques îles méditerranéennes que la présence de 

l‘oxalide dans un milieu pourrait changer la structure de la végétation et/ou réduire la 

diversité et la richesse du milieu envahi. Cependant, lors d‘une étude sur la compétition entre 

O. pes-caprae et Lolium rigidum (espèce annuelle), Sala et al. (2007) ont démontré que 

l‘oxalide est moins compétitive que le ray-grass. Ainsi, cette constatation laisse penser que 

l‘oxalide est dotée d‘un autre mécanisme d‘invasion tel que l‘allélopahtie en plus de sa grande 

production des bulbilles et sa compétition vis à vis de l‘eau et les minéraux du sol. 

Les résultats obtenus dans cette étude ont permis de démontrer qu‘effectivement l'oxalide 

émet des substances allélopathique auquelles sont sensibles les céréales. L'inhibition de la 

germination des semences et la réduction de la croissance des plantules de ces cultures laisse 

penser que les extraits aqueux de l'oxalide contiennent des substances al1élopathiques. Le 

même phénomène a été mis en évidence par Travlos et al. (2008) sur la base des essais au 

laboratoire et sous serre. Ils ont démontré que les extraits aqueux à partir des pétioles et des 

racines d‘O. pes-caprae réduisaient la biomasse de la lentille d‘eau, de la tomate, de l‘avoine 

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et de la laitue. De même, Paspatis et al. (2003) ont trouvé que l‘effet allelopathique de 

l‘oxalide était responsable de l‘inhibition de la germination et de la croissance de certaines 

mauvaises herbes telles que Parietaria sp., Amaranthus sp. et Chenopodium sp. qui sont 

considérées difficiles à combattre dans les vignobles. Dans ce cas, ils recommandaient 

d‘exploiter les infestations de l‘oxalide dans un programme de gestion intégrée des mauvaises 

herbes des vignobles. 

Tableau 5 - Effet des extraits aqueux de l'oxalide au stade floraison sur la germination et la 

croissance du blé tendre 



Aérienne 

Fraîche 

Aérienne 

Sèche 

Racinaire 

Fraîche 

Racinaire 

Sèche 

0 88,9 a* 0,09 a 0,09 a 15,5 a 9,9 a 

30 84,5 a 0,08 a 0,08 a 12,9 b 11,0 a 

60 77,8 a 0,05 b 0,09 a 12,5 b 11,2 a 

100 61,1 b 0,03 c 0,08 a 12,2 b 10,6 a 

0 75,6 a 0,08 ab 0,12 b 12,2 a 12,5 b 

30 72,2 a 0,10 a 0,14 a 12,7 a 14,4 a 

60 65,6 a 0,08 ab 0,14 a 11,1 a 13,9 ab 

100 58,9 a 0,06 b 0,11 b 8,1 b 11,6 b 

0 94,4 a 0,10 b 0,10 a 17,8 a 9,0 b 

30 93,3 a 0,13 a 0,09 a 19,3 a 11,2 a 

60 90,0 a 0,12 a 0,11 a 18,3 a 10,7 a 

100 91,1 a 0,09 c 0,10 a 17,6 a 10,9 a 

0 82,2 a 0,07 a 0,10 b 13,2 a 11,8 b 

30 76,7 a 0,08 a 0,14 a 14,1 a 13,6 a 

60 73,3 a 0,06 a 0,14 a 9,2 b 13,6 a 

100 73,3 a 0,05 a 0,10 b 5,5 c 11,2 b 




La réaction des blés dur et tendre et de l'orge varie avec l'état et le stade de l'oxalide et avec 

la concentration des extraits. Les substances allélopathiques ont un comportement semblable à 

celui des herbicides. Comparativement au coléoptile, l'effet allélopathique des extraits aqueux 

a été remarquable sur les racines. Ceci s'explique par le fait que les racines ont été exposées 

d'une façon permanente aux substances allélopathiques. Ces substances sont absorbées 

préférentiellement par le système souterrain et agissent au niveau des racines. De même, elles 

pourraient subir des transformations d'inactivation lors de leur translocation vers le système 

aérien. Ou au contraire, ces substances ont été absorbées par les parties racinaire et aérienne et 

ont subit une transformation d'activation au niveau des racines ou tout simplement il y avait 

une sélection des molécules au niveau des deux parties des plantules des céréales. D‘autres 

études expérimentales sont nécessaires pour vérifier ces hypothèses. 

L'effet des substances s‘est traduit par une réduction du poids et de la longueur du 

coléoptile et de la radicule des céréales qui pourrait être une conséquence de l'inhibition de la 

division cellulaire et/ou de l'élongation cellulaire. Effectivement, Qasem (1994) avait rapporté 

que plusieurs substances allélopathiques sont soupçonnées d'inhiber l'effet des hormones de 

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345

croissance telles que la gébberel1ine et l‘auxine. L'effet allélopathique de la partie aérienne de 

l'oxalide a tendance à être plus important que celui de la partie racinaire. Ce résultat confirme 

celui de Qasem (1995b) qui avait étudié l'effet allélopathique des amarantes sur le blé dur. 

L'effet allélopathique de l'oxalide à l'état frais laisse penser soit que certaines substances 

impliquées dans le phénomène sont volatiles et ont été perdues lors de séchage, soit que 

certaines molécules ont été modifiées par la chaleur. 

Tableau 6 - Effet des extraits aqueux de l'oxalide au stade f1oraison sur la germination et 

la croissance de l'orge 



Aérienne 

Fraîche 

Aérienne 

Sèche 

Racinaire 

Fraîche 

Racinaire 

Sèche 

0 83,3 a* 0,10 a 0,13 a 13,6 a 13,8 a 

30 91,1 a 0,08 b 0,13 a 8,0 b 14,8 a 

60 78,9 b 0,06 c 0,11 a 6,6 b 13,9 a 

100 37,8 b 0,03 d 0,08 b 1,7 c 9,5 b 

0 83,3 a 0,07 b 0,13 b 13,2 a 13,0 ab 

30 71,1 b 0,10 a 0,15 a 12,6 b 14,1 a 

60 61,1 b 0,06 bc 0,11 b 10,4 c 12,0 bc 

100 44,4 c 0,05 c 0,11 b 6,6 d 11,2 c 

0 94,4 a 0,13 b 0,13 b 17,2 a 13,9 b 

30 90,0 a 0,15 a 0,17 a 18,2 a 17,0 a 

60 92,2 a 0,11 c 0,15 a 16,7 b 16,2 a 

100 88,9 a 0,10 d 0,17 a 14,4 b 16,9 a 

0 81,1 a 0,09 a 0,12 a 14,0 a 13,2 a 

30 72,2 a 0,08 a 0,12 a 11,7 b 12,9 a 

60 61,1 ab 0,06 b 0,11 a 7,3 c 12,1 a 

100 45,6 b 0,03 c 0,09 b 4,1 d 10,6 b 




Comparativement au témoin ne contenant que de l'eau distillée, la croissance des blés dur 

et tendre et de l'orge aux faibles concentrations des extraits de l'oxalide laisse penser que la 

stimulation du poids et/ou de la longueur est dû soit aux apports des substances minérales et 

organiques, soit au fait que les extraits aqueux de l'oxalide agissent comme des 

phytohormones à des faibles doses (Qasem, 1994). 

En conclusion, l'oxalide a un effet allélopathique certain sur la germination et la croissance 

du blé dur, du blé tendre et de l'orge à travers ses extraits aqueux. Le phénomène 

d‘allélopathie mis en évidence chez O. pes-caprae est une autre facette de ses potentialités 

concurrentielles avec les plantes endémiques ou cultivées. Cependant, d'autres recherches sont 

nécessaires pour élucider ceci, connaitre la nature des substances impliquées pour chaque 

organe et pour chaque stade, s‘assurer de la constance et/ou de la stabilité de ces substances et 

exploiter cette voie de concurrence entre les végétaux pour comprendre les mécanismes 

d‘invasion biologique. 

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346

Références 

Ater M (2005) Quelques aspects de la biologie de la reproduction d’Oxalis pes-caprae L. au Maroc. Proceedings 

du Symposium National sur les Adventices Vivaces. Association Marocaine de Malherbologie, Rabat 

(Maroc).pp. 73-79. 

Jahandiez E & Maire R (1931) Catalogue des Plantes du Maroc. Lechevalier, Paris (FR). Tome 1. 

Paspatis EA, Kisarakis I & Psomadeli H (2003) Integrated weed management in oxalis infested vineyards of 

Crete. Integrated Protection and Production in Viticulture. IOBC/wprs Bulletin 26 (8), 309-311. 

Qasem J (1994) Allelopathic effect of white top (Lepidium draba) on wheat and barley. AIlelopathy Journal 1, 

29-40. 

Qasem J (1995a) Allelopathic effect of some arable land weeds on wheat (Triticum durum L.): a survey. Dirasat 

22, 81-97. 

Qasem J (1995b) The allelopathic effect of three Amaranthus spp. (pigweeds) on wheat (Triticum durum). Weed 

Research 35, 41-49. 

Ren M-X & Zhang Q-G (2009) The relative generality of plant invasion mechanisms and predicting future 

invasive plants. Weed Research 49, 449-460. 

Rice EL (1984) Allelopathy. 2 nd edition. Academic Press, London (GB). 

Rsaissi N (1994) Lutte chimique contre le brome rigide (Bromus rigidus Roth.) et 1‘oxalide (Oxalis pes caprae 

L.) dans la culture du blé dur (Triticum durum Desf.) dans la Chaouia. Mémoire de 3 ème cycle Agronomie, 

option Protection des Végétaux, I.A.V. Hassan II, Rabat (Maroc). 

Rsaissi N & Bouhache M (2005) Oxalide (Oxalis pes-caprae L.) : biologie, impact agro-économique et moyen 

de lutte. Proceedings du Symposium National sur les Adventices Vivaces. Association Marocaine de 

Malherbologie, Rabat (Maroc).pp. 145-153. 

Sala A, Verdaguer D & Vilà M (2007) Sensitivity of the invasive geophyte Oxalis pes-caprae to nutrient 

availability and competition. Annals of Botany 99 (4), 637-645. 

Tahri M (1993) La flore adventice messicole du périmètre irrigué du Haouz (Maroc occidental). Journées 

Nationales de Protection des Plantes, A.M.P. P., Rabat (Maroc). 

Tanji A (1988) Lutte contre l'oxalide (Oxalis pes caprae L.) en Chaouia. Rapport d'activité annuel, INRA, Settat 

(Maroc) 

Travlos IS, Paspatis E. & Psomadeli E. (2008) Allelopathic potential of Oxalis pes-caprae tissues and root 

exudates as a tool for integrated weed management. Journal of Agronomy 7, 202-205. 

Vilà M, Tessier M, Suehs CM & al. (2006) Local and regional assessments of the impacts of plant invaders on 

vegetation structure and soil properties of Mediterranean islands. Journal of Biogeography 33, 853-861. 

Allelopathy of Oxalis pes-caprae L. as potential invasion mechanism of winter cereal 

crops 

Native to southern Africa, Oxalis pes-caprae L. (= O. Cernua Thumb.) is an invasive weed 

widespread in areas of the world with Mediterranean climate. It is a perennial bulbaceous and 

rhizomatous dicotyledonous species which reproduce asexually by bulbils in the invaded 

range. In Morocco, this species was introduced in the beginning of the nineteenth century. It 

was regarded as a naturalized and ruderal species. Actually, it is infesting agricultural 

ecosystems. This study was conducted in order to investigate the effects of aqueous extracts 

of O. pes-caprae on seed germination and growth of three winter small grain cereal crops 

(soft wheat, durum wheat and barley). At vegetative and flowering growth stages of O. pes 

caprae, both fresh and dried shoot and roots aqueous extracts significantly reduced 

germination of the three cereal crops seeds grown in Petri dishes. In addition, these extracts 

decreased also length and biomass of cereal crops roots and coleoptiles. The allelopathic 

effect depends on cereal species, organs and growth stage of the weed. The inhibitory effect 

of extracts was more pronounced at full strength concentration. 

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347

Fitness of the populations of invasive volunteer sunflower 

Sava Vrbnicanin 1 , Dragana Bozic 1 , Danijela Pavlovic 2 & Marija Saric 1 

1 Faculty of Agriculture, University of Belgrade, Belgrade, Serbia 

2 Institute for plant protection and environment, Belgrade, Serbia 

E-mail: sava@agrif.bg.ac.rs 

Fitness or organism capability to sustain itself, survive and reproduce is the main reason for 

the spread of invasive alien weed in an ecosystem. In Serbia, in agricultural areas, edges of 

crop fields, uncultivated areas, and along roadsides we see more and more populations of 

volunteer sunflower (Helianthus annuus ruderale). This species is acting as an aggressive and 

invasive weed whose numbers are increasing from year to year and present problems in 

certain crops e.g. hybrid sunflower. To be able to estimate survival and spread it is important 

to study fitness: reproductive (vegetative and sexual) and competitive capability, possibility 

for hybridization, seed germination, and other physiological and genetic characteristics as 

indicators of capacity for spreading under conditions where herbicides were and were not 

applied. 

In this experiment we studied three different populations of volunteer sunflower under field 

vs. controlled conditions and with and without application of herbicide nicosulfuron. Two 

populations originated from areas where herbicides ALS-inhibitors were used for many years 

(P1 and P2) and the third population originated from areas where herbicides have not been 

applied (P3). The following parameters were evaluated: plant height, fresh weight, leaf surface 

area, anatomical characteristics, effects to increasing nicosulfuron rates, amount of 

chlorophyll, activity of ALS enzymes in vitro, seed germination, yield and yield parameters. 

In general, population fitness depended on the year in which the sampling was conducted and 

was better with presumably resistant populations (P1 and P2) vs. susceptible population (P3) 

for larger numbers of evaluated parameters (fresh weight, leaf surface area, amount of 

chlorophyll, yield parameters, seed germination, activity of ALS enzymes in vitro) under 

conditions without nicosulfuron and when nicosulfuron was applied (height, fresh weight, leaf 

surface area, amount of chlorophyll, seed germination, leaf anatomical characteristics). 

In summary, relative fitness of different populations (susceptible and presumably resistant 

populations) of volunteer sunflower under conditions w/o herbicide applications is one of the 

most important factors which influence its survival and spread as an invasive alien weed 

species in an ecosystem. Our strategies for prevention of spread of volunteer sunflower need 

to be developed according to fitness. 

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348

Nicotina glauca: an invasive alien with harmful potential 

Stephen L Jury & JD Ross 

School of Biological Sciences, Harborne Building, University of Reading, Whiteknights, 

Reading RG6 6AS, UK 

E-mail: s.l.jury@reading.ac.uk 

In recent years Nicotiana glauca Graham has spread considerably throughout the 

Mediterranean and has even been recorded recently in ruderal situations in Southern England. 

Regular fieldwork in Spain and Morocco has enabled us to undertake projects and obtain 

detailed observations. 

The species is native to Argentina and Bolivia where it is hummingbird pollinated. However, 

the breeding system has changed allowing regular high seed production in its well naturalized 

regions of Europe, North Africa, North America, Australia and New Zealand. This, in 

association with its ability to colonise dry watercourses, allows it to spread rapidly in frostfree 

drier regions. The temperature of the leaves indicates a high transpiration rate 

demonstrating the plant‘s ability to obtain water, even in semi-arid conditions coupled with a 

very high photosynthetic rate, characteristic of such nitrophilous invasive species. 

Additionally, it is a vigorous resprouter if cut back, and accumulates anabasine, a highly 

poisonous alkaloid, giving protection against most herbivores, although remarkably not a 

deterrent to a narrow range of caterpillars, whitefly and molluscs. Very recently we have seen 

it infected by tobacco mosaic virus, making it a potential danger to locally cultivated tomato, 

aubergine and pepper crops, as well as the cucurbits, also well known as susceptible to this 

pathogen. 

However, websites show some seed suppliers offering innocent amateur gardeners an 

opportunity to grow and evaluate the species for ornamental horticulture. The continued 

spread of this species must be checked in order to preserve native habitats and protect 

economically important crop production. 

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349

Tree of Heaven (Ailanthus altissima) – Establishment and invasion in Croatia 

V. Lodeta, N. Novak, M. Kravaršţan 

Croatian Centre for Agriculture, Food and Rural Affairs, Institute for Plant Protection, 

Svetošimunska 25/V, 10040 Zagreb, Croatia. E-mails: veljko.lodeta@zg.t-com.hr, 

nenad.novak@hcphs.hr, maja.kravarscan@hcphs.hr 

Introduction and distribution 

Tree of heaven (Ailanthus altissima (Mill.) Swingle, family Simaroubaceae, 

order Sapindales) is a deciduous tree native to China. It was introduced into 

Europe in the late 1700s as an ornamental species. Nowadays, it is 

distributed in warm climatic areas of the world. 

A. altissima is one of species listed on the EPPO List of invasive alien 

plants. It grows quickly and can reach a height of 2.5 m in its first year. It 

can grow rapidly up to 35 m, while its trunk can reach more than 1 (1.5) m 

in diameter. The bark and leaves reportedly produce allelopathic chemicals 

that accumulate in the soil and can cause mortality in other vegetation. The 

foliage is unpalatable to browsing wildlife and can cause allergic reactions 

on the skin. Because of its rapid growth, foresters use to plant this species 

for erosion control. In ornamental plantations it is often used as decorative 

plant. 

In Croatia, it is present in the whole country but is especially aggressive in 

the Adriatic coastal part (from Istria to South Dalmatia). In some parts of 

the continental regions, in costal parts and in some islands, it kills native 

vegetation and often forms dense monocultures. 

This species reproduces both from seed and root sprouts. Young plants 

emerge near to adult trees in very large numbers and commonly distribute 

locally. Human impact is a very important factor of Ailanthus colonization. 

It is usually found near busy roads, in towns, building sites and industrial 

yards. It is hardly ever found in undisturbed environments and stable 

ecosystems. 

Tree of heaven (Ailanthus altissima (Mill.) Swingle, family Simaroubaceae, order 

Sapindales) is a deciduous tree native to China (Press, Hosking 1992., 

http://www.nps.gov/plants/alien/). It was introduced into Europe in the late 1700s as an 

ornamental species (http://www.nps.gov/plants/alien/fact/aial1.htm). The propagation with 

seeds and root buds is simple and plant producers like this species (Toogood & Anderson, 

2006.). Because of its rapid growth, foresters used to plant this species for erosion control. In 

ornamental plantation it is often used as a decorative plant. Nowadays, it is distributed in 

warm climatic areas of the world (http://www.eppo.org/QUARANTINE/ias_plants.htm). 

Ailanthus altissima is one of species listed on the EPPO List of invasive alien plants. It is 

distributed in warm climatic areas of Africa, America, Australia, New Zealand and in Europe 

from Bulgaria to the British Isles, with a Northern distribution bordering Germany 

(http://de.wikipedia.org/wiki/Götterbaum). 

In Croatia, it is present in many places. It can be found almost everywhere. It is especially 

aggressive in the Adriatic coast, from Istria to Southern Dalmatia (Novak et al 2009.). In 

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350

some parts of the continental regions, in many locations on coast and islands, it kills native 

vegetation and often forms dense monocultures (Lodeta, Novak, 2010.). 

Human activities are a very important factor in the colonization and spread of tree of 

heaven. Usually it is found near traffic roads, in towns, in building sites and in industrial 

yards. It is hardly found in stable ecosystems and untouched environment (Radoshevich et al. 

2007.). 

Reproduction and colonisation 

Tree of heaven is intolerant to shade (Grime 1979 cit. Radoshevich 1984). In natural 

habitats reproduction is primarily from seeds. They are easily windblown and high 

percentages of them are viable, 30% germination rate for seeds that overwintered on parent 

trees and dispersed in spring (Kowarik, Saumel, 2008. & Hunter, 1995. cit Fryer, 2010). 

Many young plants are emerging at the base of mother plants. Tree of heaven grows quickly 

and can reach a height of 2.5 m in its first year. It can grow rapidly to 25 m (Weber, 2005). A 

fact sheet states that tree-of-heaven may reach 80 feet (20 m) tall and 6 feet (2 m) in diameter 

in 10 years (Evans et al., 2006) The trees are typically short-lived (30-50 years), though some 

have survived for over 150 years. In our climatic and weather condition the plant can rich the 

high of 20 m and the trunk diameter until 50 cm. (Vukiţeviš, 1974) 

Flowers are unisexual, small and yellow, in large panicles at the end of the branches. Fruit 

are dry, indehiscent, light brown to yellowish, winged samaras of 25-50 mm length and 6-10 

mm width, containing one seed of 3-5 mm diameter in the centre (Weber, 2005). 

Tree of heaven grows mostly in sunny positions on humid soils. It can resprout rapidly 

after being cut (Sušiš, Radek, 2007). It has been noted as a drought-tolerant plant 

(http://www.eppo.org/QUARANTINE/ias_plants.htm), storing water in its root system 

allowing its survival on shallow karst soils in Croatian Mediterranean region. The seeds are 

produced in spring from the mother plants, both on Croatian Mediterranean and continental 

area. During summer, drought slows down further development of young plants on shallow 

karst soils, but it is important to note that the tree of heaven survives these poor conditions 

and can spread further after this period (Lodeta, Novak, 2010.). Tree of heaven has the ability 

to grow in poor soils and under environmentally stressful conditions such as low nutrient and 

oxygen content and can tolerate barren rocky hills if annual rainfall is above 750 mm (Zheng, 

1988 cit. http://www.eppo.org/QUARANTINE/ias_plants.htm). A. altissima is found at a 

range of altitudes up to 2400 m. Tree of heaven grows best on loose and porous soils, but can 

grow on a variety of soil types from heavy clays, sandy or clayey loams to calcareous dry and 

shallow soils. 

Tree of heaven doesn‘t grow in closed forests or parks as it does not tolerate overshadow 

(Grime, 1979 cit. Radoshevich, 1984) and stays more or less on borders although it competes 

well with many plant species (Lodeta, Novak, 2010). Non-arable land near roads, railways, 

industrial sites and streets are suitable for the development of tree of heaven. In continental 

area of Croatia, unfavourable winter conditions can cause the deterioration of the plant (cold 

and wind, saprophyte fungi, mechanical stem damages and salt for snow melting). In such 

conditions, Ivy (Hedera helix L.) sometimes overgrow tree of heaven. 

Control measures 

Control measures are only used sporadically in Croatia, no awareness on invasive alien 

plants exists and there is no legislation about mandatory control measures for the containment 

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351

or the eradication of A. altissima. To prevent damages of invasive alien species it is necessary 

to have a good communication among agricultural, forestry and other experts involved in 

plant growing to avoid any misunderstanding in the whole EPPO region. Informing the 

general public is a very important control measure for all invasive alien species. 

Conclusions 

- A. altissima gradually and successfully colonize many areas of Croatia; 

- On many locations, tree of heaven kills native vegetation and forms dense monocultures 

- Tree of heaven is especially aggressive in the Adriatic coastal area 

- It tolerates droughts better than many other species 

- Established plants of A. altissima are permanent source of new seeds; 

- When a mother plant is weak or damaged young plants emerge from root buds; 

- Non-arable land near roads, railways, industrial sites and streets are suitable for the 

development of tree of heaven; 

- Tree of heaven doesn‘t grow in closed forests or parks because it doesn‘t tolerate 

overshadow stays on border although it competes well with many plant species; 

- Young trees of heaven as well as the old ones grow through bushes, in poorly maintained 

courtyards, near parking places etc; 

- Winter conditions influence on the deterioration of the plant (cold and wind, mechanical 

stem damages and salt for snow melting); 

- The consequences of these unfavourable conditions are damages and deteriorations caused 

by saprophyte fungi; 

- Ivy (Hedera helix L.) sometimes overgrow tree of heaven, weakens its growth and 

development and causes deterioration. 

References 

EPPO data sheet on Invasive Plants, Ailanthus altissima http://www.eppo.org/QUARANTINE/ias_plants.htm 

Evans CW, Moorhead DJ, Bargeron CT & Douce GK (2006) Invasive plant responses to silvicultural practices 

in the South. Bugwood Network BW-2006-03. Tifton, GA: The University of Georgia Bugwood 

Network. 52 p. 

Fryer JL (2010) Ailanthus altissima. In: Fire Effects Information System, [Online]. 

http://www.fs.fed.us/database/feis/plants/tree/ailalt/all.html 

Grime JP (1979) Plant Strategies and Vegetation Processes. Wiley New York. 

Lodeta V, Novak N (2010) Unpublished Data of the 4 years Monitoring Programme Invasive Alien Plants in 

Croatia. 

Novak N, Lodeta V, Sušiš G & Radek V (2009) Tree of Heaven (Ailanthus altissima (Mill.) Swingle) - Invasive 

Alien Species in Croatia, BIOLIEF – World Conference on Biological Invasions and Ecosystem 

Functioning, 27th-30th October 2009, Porto, Portugal page 135 

Press B, Hosking D (1992) Trees of Britain and Europe. New Holland Publishers, London. p. 182. 

www.newhollandpublishers.com 

Radosevich SR, Holt JS & Ghersa CM (2007) Ecology of Weeds and Invasive Plants, 3 th Edition. John Wiley & 

Sons, Inc., Hoboken, New Jersey, USA, pp. 56-62. 

Sušiš G & Radek V (2007) Project: Developing and management plan for alien invasive plant and animal 

species on the Island of Cres 

Toogood A & Anderson P. (2006) Propagating Plants, 2 nd Edition. The Royal Horticultural Society, Dorling 

Kindersley Limeted, London, 75. 

Vukiţeviš E (1974) Dekorativna dendrologija (Decorative dendrology). ICS (Izdavaţko-informativni centar 

studenata (ICS) Beograd. P. 284. 

Weber E (2005) Invasive Plant Species of the World. A Reference Guide to Environmental Weeds. CABI 

Publishing, page 32. 

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352

Effect of Ambrosia artemisiifolia invasion on public health and agricultural production 

in Hungary 

MN Okumu, É Lehoczky 

University of Pannonia Georgikon Faculty, Institute of Plant Protection 

H-8360, Deák F. Str. 57. Keszthely, Hungary. E-mail: nelmak2212@yahoo.com 

Introduction 

Ambrosia genus which consists of about 40 species is considered to be the 

most dangerous invasive alien species of Europe. Common ragweed 

(Ambrosia artemisiifolia L.) is the most important invasive plant species 

with an allergenic effect. This plant originates from North America and has 

evolved to suit a dry climate and open environment. In Hungary, almost 

80% of the arable land is infested and ragweed has become the most 

important weed in agricultural crops during the last 20 years. Twenty five 

percent of the Hungarian population suffer from allergy to its pollen. In 

Europe, all the highest pollen counts on peak days are reported from the 

Carpathian Basin, Serbia and Hungary. It has been shown from several 

studies, that A. artemisiifolia contains allelochemicals, which may play an 

important role in artificial and natural ecosystems. The importance of A. 

artemisiifolia as an acceptor species is less known. 

The distribution of Ambrosia artemisiifolia in Europe started after the First World War 

(Comtois 1998). The results of the Four National Weed Surveys in Hungary proved that big 

social changes preceded A. artemisiifolia invasion, which is closely linked to human 

activities. Its introduction and naturalization in Europe was as a result of a high volume of 

movement of transports of food-products and war equipment from the USA towards Europe 

during the First Word War (Makra et al., 2005). Its rapid distribution is in close relation with 

the cereal transport during the Second World War and land distribution to farmers in Hungary 

after the war. A. artemisiifolia in the last two decades has become the most recognized weed 

species in Eastern-Europe. This is because so many people developed allergies to its airborne 

pollen, thus forcing national governments to initiate programs aimed at bringing attention to 

this noxious weed (Járai-Komlñdi, 1998). The objective of this paper is to give details on the 

biology of Ambrosia artemisiifolia, its entry pathway and distribution in Hungary, its effects 

on public health and agricultural production and the legal regulations put in place to combat 

the spread of the weed. 

Biological characteristics of Ambrosia artemisiifolia 

Common ragweed (A. artemisiifolia) is a summer annual branchy herb (Soñ, 1970, 

Ujvárosi, 1973) with rough, hairy stems. It belongs to the Asteraceae family, and to the genus 

Ambrosia, which has 42 species. Common names include common ragweed, annual ragweed, 

low ragweed, ragweed, Roman wormwood, short ragweed and small ragweed. It is a 

therophyte with an erect and is a rather tall plant reaching a maximum height of 2 metres 

usually with many branches (Basset et. al., 1975). Ramification starts about 2-4 cm above the 

ground and may include numerous side-branches. Leaves are short-stalked, hairy, ovate in 

outline, with lobed segments on each side. The lower leaves are arranged oppositely while 

upper leaves are often arranged alternately on the stem. Female flowers are inconspicuous, 

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353

located solitarily or in small groups at the base of upper leaves. Male flowers are green and 

small (2-4 mm) grouped in spike-like flower heads (racemes) at the end of the upper 

branches. 

Juhasz (1963) reported the appearance of three Ambrosia species in Hungary, namely, A. 

elatior, A. artemisiifolia and A. psilostachya. On the basis of the latest taxonomic research, A. 

elatior and A.artemisiifolia are considered as the same species and are synonym names of 

each other. The presence of the perennial A. psilostachya was reported in Csepel and 

Szigetvár towns in Hungary along the railway stations. 

Life cycle of A. artemisiifolia in Hungary 

Field emergence of A. artemisiifolia shows seasonal changes in Hungary (Béres & 

Hunyadi, 1980), with a beginning at the end of March. On the basis of a 20-year research 

observation (1976-1996), the appearance of the first seedlings can be expected between 

March 15 and April 12 in Keszthely (Zala county, Hungary) (Table 1). The germination peak 

is in April and May. Sixty percent of seeds germinate between April 10 and May 20. A part of 

the seeds fail to germinate from middle of May due to the secondary dormancy, therefore 

germination decreases by this time. Due to the hot summer periods, secondary dormancy may 

be induced in the seeds (Milanova & Nakova, 2002). 

Table 1 - Beginning dates of Ambrosia artemisiifolia phenophases under field conditions 

(Keszthely, Hungary, 1976-1996, after Béres, 2003) 

Years Average temperature Beginning of Beginning of Beginning of 

of March (°C) germination flowering seed ripening 

1976 7.2 20 th March 18 th July 2 nd Oct 

1977 7.8 25 th March 25 th July 3 rd Oct 

1978 6.3 30 th March 3 rd August 6 th Oct 

1979 9.6 22 nd March 12 th July 4 th Oct 

1980 5.0 28 th March 31 st July 12 th Oct 

1981 8.3 25 th March 21 st July 5 th Oct 

1982 5.8 26 th March 25 th July 11 th Oct 

1983 6.8 17 th March 21 st July 30 th Sept 


1985 3.7 2 nd April 23 rd July 14 th Oct 

1986 2.6 5 th April 24 th July 20 th Oct 




1990 8.9 18 th March 20 th July 1 st Oct 





1995 4.4 30 th March 3 rd August 28 th Oct 


After May, germination rate increases again but never reaches the April maximum. From 

August, germination decreases drastically again, though it can occur continuously until the 

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first frosts. Temperatures suitable for seed germination of A. artemisiifolia ranges from 8 to 

36 0 C (Hsu, 2005). After germination, the weed grows rapidly during the juvenile phase under 

optimum conditions promoting the competitive ability of the plant. Intensive growth 

continues to its maximum directly before flowering. Common Ragweed germinating in cereal 

fields may remain in the juvenile stage until the crop is harvested and then start to grow when 

exposed to light (Bohren, 2006). 

Figure 1 - Life cyle of A. artemisiifolia in Hungary (Béres & Bìrñ, 1993) 

The plants usually flower in the period July to October and seeds are produced from mid 

August. The appearance of the first female flowers can be expected between July 12 and 

August 3. The first ripened seeds occur on September 30. The rather late flowering and 

maturation of the seeds limits the distribution of the plant to climate zones with a long 

growing season. (Béres – Hunyadi, 1980, Kőmìves et al., 2006). 

Reproduction strategy 

As a summer annual, A. artemisiifolia can propagate only by seeds, 95% of the plants are 

monoecious. Seed production varies between 0 and 62,000 seeds per plant, depending on 

plant size, growing technologies, competition and ecological factors. Under average 

conditions, 3000 seeds per plant are established when seeds germinate at the beginning of 

April. When seeds germinate in August, only 4-6 seeds develop (Béres & Hunyadi, 1980). In 

the experiments of Bassett & Crompton (1975), A. artemisiifolia plants produced 32000 seeds 

when germination was before middle of May and only 3100 seeds when germination was 

later, in July. 

Viability of freshly harvested seeds in Hungary varies between 92 and 96% and remains 

viable after 20 years of burial. Twelve to fifteen weeks must be attained after seed harvesting; 

by the second half of February, for germination rate to be above 80% (Hartmann et al., 2003). 

Freshly harvested seeds in autumn are in primary dormancy (Béres, 1981), which is due to the 

inhibitors present in the pericarpium (Wareing, 1975). The ability of A. artemisiifolia to adapt 

to germination characteristics can be explained by its pioneer disturbing strategy. After soil 

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cultivation, light reaches the seeds. Therefore, germination occurs but not all seeds germinate, 

in order to ensure survival of the species. On the other hand, secondary seed dormancy in 

summer prevents germination under less favourable conditions (Szigetvári & Benkő, 2004). 

Adaptability and Survival under adverse conditions 

Ambrosia artemisiifolia is a plant with remarkable flexibility in its biology which has 

contributed to its ability to exploit new habitats. In Hungary, this weed was able to enter the 

ecosystem in areas far outside its normal geographical range and adapted to different climatic 

and soil conditions (Berés & Hunyadi, 1980). This ragweed species produces different forms 

(varieties) as an effect of adaptation to different conditions. Seeds may survive for many years 

in conditions insufficient for the development of other plants. Common ragweed is able to 

adapt to mowing, trampling and grazing and responds to, and counteracts the effects of 

cultivation and ploughing, by the longevity of its seeds (Toole & Brown, 1946). 

Habitat description and countrywide distribution 

The rapid distribution of A. artemisiifolia began after the Second World War. A. 

artemisiifolia is greatly distributed on the Southern part of Europe, the Balkan Peninsula 

(Kovacevic & Miller, 1958), middle and South America, Asia and Australia. There are three 

main regions invaded by Ambrosia in Europe: the valley of the Rhone (France), Northern 

Italy and the Carpathian Basin (Rybnicek & Jager, 2001). Seeds of A. artemisiifolia were 

introduced into Hungary through the Adriatic ports of the historic Austro-Hungarian Empire 

as a contaminant of agricultural products (Makra et al., 2005). Its spread took place along 

linear structures, such as highways, railways and watercourses. 

By now, extensive A. artemisiifolia populations are in Hungary and France, extensive 

spreading beginning in Italy, Germany, Austria and Switzerland. On the basis of the latest 

surveys, rapid distribution of A. artemisiifolia can be observed in Austria, Slovakia, Poland, 

Turkey and Korean Peninsula. Northern border of its contiguous distribution is on the 

southern part of Poland and Germany (Kazinczi et al., 2008). 

As an arable weed, A. artemisiifolia was reported in the first half of the 1920‘s. Its first 

appearance was proven in 1922, on the South- Transdanubian part of Hungary, near 

Somogyvár (Somogy county). A. artemisiifolia was introduced from the neighbouring parts of 

the former Yugoslavia, and after then it spread to other parts of Hungary (Kazinczi et al., 

2008). At present it is generally distributed throughout Hungary, except places with extreme 

soil conditions and higher lands with cold climates. Lengyel (1923) reported A. artemisiifolia 

in Somogy, Zala and Veszprém counties, Szigetszentmiklñs and Somogyvár (Moesz, 1926) 

and in Örkénytábor (Boros, 1938). Between the Danube and Tisza rivers, A. artemisiifolia 

was distributed from Szeged town towards the Northern parts of Hungary (Tìmár, 1955). Its 

occurrence near Csurgñ was reported by Héjjas and Borhidi (1960). A. artemisiifolia infested 

an area of more than 380 000 hectares in 1986. In 2003, the weed was present on 5.4 million 

hectares, of which 700 000 hectares were heavily infested (Tñth et al., 2004). Sixty percent of 

Ambrosia infested areas consist of such fields, which are greater than 5 ha. 

The last boom in its spread could be linked to the political transitions that led to the 

formation of young democracies in Eastern Europe. During that process, virtually all socialisttype 

agricultural co-operatives were closed and their lands subdivided and redistributed to 

their former owners or descendants, who in many cases did not continue to cultivate them for 

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years. The large and formerly well-kept agricultural fields were abandoned and quickly 

colonized by A. artemisiifolia (Makra et al., 2005). In addition, new roads, motorways and 

shopping centres were built, but little effort was put into landscape management. This created 

large disturbed areas, where the weed readily became established. In less than a decade, A. 

artemisiifolia became the most widespread weed species in both agricultural and urban areas 

in Hungary, as well as many neighbouring countries, with the notable exception of Austria, 

where landscape management remained unchanged (Kiss and Béres, 2006). It is interesting to 

note that the Eastern European spread of A. artemisiifolia is associated not only with the 

collapse of communism, but also with its inception. Soon after 1945, when socialist-type 

cooperatives began to be formed, A. artemisiifolia populations started to spread in many fields 

(Béres, 2003). 

Figure 2 - Phases of A. artemisiifolia distribution and spread in Hungary (Priszter 1960, 

Béres & Hunyadi 1991). 

A. artemisiifolia was reported in Lithuania and Ukraine (Gudzinska, 1993). The plant 

quarantine service in Russia reported the occurrence of A. artemisiifolia in Kuban 

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(Vysokopoyasnyi, 2004) and in the Rostov region, southern Russia. It is suggested that A. 

artemisiifolia was introduced into western Ukraine through infested grain from southern 

regions (Zagolovski et al., 2004). In Bulgaria, the weed was found for the first time in the 

region of Kostinbrod in 1995, by the railway. The species is distributed in the Danubian Plain 

and Sofia Region (Assyov et al., 2001). A. artemisiifolia is included in the list of quarantine 

weeds in Bulgaria. 

In Hungary, A. artemisiifolia is considered to be a common weed in field crops, especially 

in sunflower and maize. During harvest, cucurbit fields (especially pumpkin and melon) 

become strongly infested with A. artemisiifolia (Szentey et al., 2004). It also occurs in 

pastures, meadows, vineyards, orchards and forestations, along road and railway sides and 

ditches. A. artemisiifolia, as a pioneer species of secondary succession, is dominant in 

undisturbed areas in the first year and it is replaced by perennials in the subsequent years 

(Maupin & Apparicio, 2004). It prefers full sun and warm areas, with nutrient rich and 

slightly acidic soils (Wittenberg, R. (ed.) 2005) and can tolerate dry soil conditions (Maupin 

& Apparicio, 2004). It is dominant on haplic cambisols, sandy soils and on fluvisols (Béres & 

Hunyadi, 1991). The most favorable for its development are the slightly acidic (pH, 6.6-7.0) 

sandy adobe and muddy loam soils. 

On the summarized list of weed flora of winter wheat and maize at the time of the First 

National Weed Survey in 1950, A. artemisiifolia was the 21 st most important weed (Tñth et 

al., 1999). Forced creation of collective farming which ended in the late 1950‘s, followed by 

the establishment of large scale farms and distribution of land gave further impetus to the 

spread of A. artemisiifolia. This weed species moved to 8 th and then 4 th place in the 

dominance order of weeds in 1970 and 1988, respectively. 

Figure 3 - Ambrosia infestation in Hungary based on the results of the Fifth National 

Weed Survey (2007-2008) 

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Effects of Ambrosia artemisiifolia on Public health – Pollen allergy 

Common ragweed represents a very serious health risk for humans as a pollen-allergenic 

plant (Taramarcaz, et al., 2005). At least six groups of allergenic agents have been identified 

in ragweed pollen (Wopfner et al., 2005). Some of these are called ‗major‘ for their 

predominant role in causing allergy in humans. Allergies to Ambrosia pollen were first 

described by Wyman in the United States during the second half of the 19 th century. Pollen of 

ragweed is among the most potent triggers of hay fever and allergic rhinitis. In addition to 

allergic rhinitis, ragweed allergy often causes severe asthma-like symptoms. Its impact is not 

restricted to areas invaded by the plant. Due to wind-borne spreading of the very large 

amounts of light pollen, ragweed may cause allergy in distances over 200 km off the site 

where it is growing. Very low concentrations, e.g. 5-10 pollen per cubic meter of air suffice to 

trigger allergic reactions in hyper-sensitised individuals. Concentrations between 6 and 10 

pollen grains per cubic meter air represent a moderate load of ragweed pollen (Wopfner et al., 

2005). 

About one-third of Hungarian inhabitants have some type of allergy, two-thirds of them 

have pollen sensitivity and at least 60% of this pollen-sensitivity is caused by Ambrosia 

(Járai-Komlñdi, 1998) with 50-70% of allergic patients being sensitive to ragweed pollen. 

Pollen counts identified airborne A. artemisiifolia pollen in Hungary for the first time in the 

late 1960s and since then, its concentration, measured during its main pollination period has 

increased dramatically. The number of patients with registered allergic illnesses has doubled, 

and by the late 1990s the number of cases of allergic asthma has over the last 40 years 

become four times higher in Southern Hungary. Therapeutic costs of allergic people and 

connected losses are estimated around 30 billion HUF (110 million EURO) per year (Tñth et 

al., 2004). Beside its pollen allergy, the plant can cause contact dermatitis. Volatile oils of A. 

artemisiifolia pollen have a photo sensible effect, causing phyto - photodermatitis (Hjorth et 

al., 1976). 

In annual totals of pollen counts of various plants measured between 1990 and 1996 in 

Southern Hungary, A .artemisiifolia produces about half of the total pollen production 

(47.3%). Although this ratio highly depends on meteorological factors year by year (in 1990 

this ratio was 35.9%, while in 1991 it was 66.9%), it can be considered the main aero 

allergenic plant in Hungary (Makra et al., 2004). It was found that the daily Ambrosia pollen 

counts are over 20-30-50 pollen grains per m 3 of air for 33-61, 27-57 and 16-50 days 

respectively of its 3-month long season, indicating severe pollen load in the air (Makra et al., 

2005). The air is most polluted with Ambrosia pollen grains in August and September. The 

period of pollen load with pollen counts over 50 pollen grains per m 3 per day was found to be 

between mid-August and mid-September. 

Skin prick test for radio allergosorbent test reactions to A. artemisiifolia allergens in pollen 

allergic European patients performed in the late 1990s gave positive results of more than 80% 

in Hungary, nearly 70% in northern Italy, 30 to 40% in the Rhone area (France), 

approximately 35% in Prague, 25 to 30% in Vienna (Austria) and approximately 19 to 25% in 

Brno (Czech Republic) (Rybnicek & Jager, 2001). 

The strong allergenic characteristic of A. artemisiifolia pollen is due to its very effective 

antigens with rapid diffusion ability. After reaching the mucous membrane of the nose, the 

allergens can diffuse within a few seconds from the pollen, therefore symptoms are expressed 

rapidly. Two novel serine endopeptidases from A. artemisiifolia pollen have been described 

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which possess the ability to exacerbate the complications of allergic rhinitis and polleninduced 

asthma. It is suggested that A. artemisiifolia proteolytic enzymes described may play 

a crucial role in the diseases associated with pollen exposure. 

Table 2 - Annual total counts of A. artemisiifolia pollen (list of the highest reported 

counts, pollen grains m 3 of air) in Hungary and neighboring countries. (Makra et al., 2005) 

City Country Year Annual 

total count 

Novi Sad Serbia 2001 20559 

Szeged Hungary 1994 17242 



Pécs Hungary 1994 15092 

Pécs Hungary 1993 13625 

Novi Sad Serbia 1999 11246 

Szekszárd Hungary 1994 9938 

Zalaegerszeg Hungary 1994 8478 

Budapest Hungary 1993 6753 

Debrecen Hungary 1993 3202 

Vienna Austria 1992 1869 

Brno Czech Republic 1995 1685 

Bratislava Slovakia 1994 1569 

Lugano Switzerland 1994 932 

Sofia Bulgaria 1993 179 

In Europe, all the highest counts on peak days were reported from the Carpathian Basin, 

Serbia and Hungary. Novi Sad (Vajdaság region of Serbia-Montenegro), the southern part of 

the Great Hungarian Plains (Szeged) and southwest Hungary (Pécs) have the highest 

concentrations of A. artemisiifolia pollen, not only in the Carpathian Basin itself but in the 

whole European continent. Values recorded in Europe on peak days have never exceeded that 

of the 3247 pollen grains m 3 of air recorded in Novi Sad in 2001. When considering annual 

totals, the highest Ambrosia pollen counts in Novi Sad and Szeged are several times higher 

than the total amount of pollen in the most intensely polluted cities of Austria, the Czech 

Republic, Slovakia, Switzerland and Bulgaria (Makra et al., 2005) (Table 2). High pollen 

concentrations of 9000m 3 per day or more frequently occur in Hungary (Kőmìves et al., 

2006). The early pollen production of Ambrosia is unimodal, starting around 8 a.m. and with a 

maximum around noon (Makra et al., 2005). 

Besides Hungary, other European countries have also detailed data about Ambrosia 

pollinosis. In 2002, A. artemisiifolia pollen was detected in the air of Wroclav city in Poland 

and the grain density ranged from 10 to 145 m 3 /hr (Malkiewicz & Wasowicz, 2003). Spread 

of A. artemisiifolia and Ambrosia pollinosis has become a rapidly emerging problem in Italy 

(Politi et al., 1992). In 21 cities across Italy, among 2934 patients with respiratory diseases of 

suspected allergic origin, Ambrosia pollen was shown to provoke asthma much more 

frequently than any other pollen grain (Corsico et al., 2000). 

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Effect on Agricultural production 

A. artemisiifolia is a noxious agricultural weed (Kazinczi et. al., 2008). By the time of 

harvest, the weed can create a dense stand in cereals and continuous ground cover in wheat 

stubbles. It can suppress other weed species, due to its allelopathic and competitive ability. It 

can cause considerable yield losses, mainly in row crops. It is very harmful in maize, due to 

its rapid growth. In the first two years after soil cultivation, A. artemisiifolia is expected to 

become the dominant weed species on fallow land. As succession proceeds, its dominance is 

considerably reduced and it is replaced by perennials. A. artemisiifolia appears in large 

quantities among stubbles in the Great Hungarian Plain (Kazinczi et al., 2008). Since 

Ambrosia is not an old adventive species of the Hungarian flora, it does not have any natural 

competitors. 

It has been proven, that A. artemisiifolia, similar to other plants, contains allelochemicals 

(Takács et al., 2004). Under laboratory conditions, in bioassay studies, the inhibitory effects 

of the plant extracts on different test species (amaranth, winter wheat, Trifolium spp, white 

mustard) were proven. The effect of the leaf extracts was the strongest, similar to that of the 

flower extracts (Brückner, 2001). In germination tests, water, alcoholic and acetonic extracts 

of A. artemisiifolia plants reduced the germination rate of soybean, maize, sunflower, pea and 

bean by 20-54% (Kazinczi et al., 2008). Phenoloids, terpenes, sesquiterpene lactones and 

volatile materials were responsible for the allelopathic effects (Geismann et al., 1969). 

Management and control options for common ragweed in Hungary 

Results of a research carried out in Hungary showed that the time and number of mowing 

greatly influence the vegetative biomass and pollen production of A. artemisiifolia (Kazinczi 

et. al., 2008). When mowing was done in the middle of May, considerable increase in fresh 

weight and pollen production was observed. After mowing, the plant developed strong side 

shoots, the leaf number and leaf area increased as compared to control (unmowed) plants. 

When mowing was done at the end of June, the height and the fresh weight of A. 

artemisiifolia plants considerably reduced. If mowing was to be done once a year, the best 

time to do it would be directly before flowering (in the middle of July). In this case, the 

number of the male flowers could be reduced by 87.7%, as compared to the control plants 

(Kazinczi et. al., 2008). In case of two mowings, the height of the plants and number of male 

flowers reduced by 49.5%. Three times mowings resulted in a 43% and 90% reduction in 

plant height and number of male flowers, respectively. In Switzerland, Bohren (2006) 

reported that at least four mowings may be successful. 

From the point of biological control, Tarachidia candefacta and Zygogramma suturalis 

insects have been used for classical biological control in the former Soviet Union (Goeden & 

Teerink, 1993). In Hungary, no insect introduction has been permitted so far. A. artemisifolia 

plants as a host of different aphids and biological decline of A. artemisiifolia plants due to the 

strong aphid infestation were studied under glasshouse conditions. Basky (2007) reported 

significant reduction in the plant height, length of flower spikes, dry weight of the plants, 

number of male inflorescences and the airborne pollen emission of the ragweed plants 

artificially infested with 5 aptera individuals of Aphis fabae, Brachycaudus helichrysi and 

Myzus persicae indigenous aphid species. 

Until now the occurrence of ten phytopathogen fungi was identified from Ambrosia plants 

(Kiss et al., 2003). In the rainy year of 1999, a Phyllacora ambrosiae epidemic seemed to be 

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promising for biological control. The disease symptoms were observed in all parts of Hungary 

at the same time. The epidemic caused considerable damage to A. artemisiifolia. The pollen 

emission season was shortened by one month (Kiss et al., 2001). Unfortunately, the 

Phyllachora epidemic did not recur and after 1999, the fungi rapidly disappeared. In 2001, 

Plasmopara halstedii attack on Ambrosia caused a 90% reduction in pollen concentration 

(Kiss et al., 2003). Unfortunately, this fungus is considered to be one of the most important 

pathogens of sunflower. On the basis of Kiss et al. (2003), six fungi from America (Puccinia 

xanthii, P. canaliculata, P. conoclinii, Entyloma polysporum, E. compositarum and 

Protomyces gravidus) seem to provide promising prospects for the biological control of A. 

artemisiifolia. Recently, a new Septoria species, S. epambrosiae was isolated from A. 

artemisiifolia in Hungary, which may also be used as a biocontrol agent for this noxious weed 

(Farr & Castlebury, 2001). 

The chemicals available for common ragweed control are constrained by country, regional 

and local regulations. A. artemisiifolia rarely occur in dense, autumn-sown crops such as 

cereals and winter rape, but in thinned stands and stubbles it may be dominant. Generally, 

control in the autumn-sown rape and cereals is not necessary, because of spring germination 

of A. artemisiifolia. When it occurs, triasulfuron in pre-emergence and post-emergence 

treatments is effective in winter wheat. In spring, hormone-type herbicides (2,4-D, MCPA, 

dicamba), and some sulfonylureas ( sulfosulfuron, chlorsulfuron) are effective against the 

weed. In rape, clopyralid+picloram combination is effective (Szentey et al., 2004). In IMI 

maize, imazamox gives an excellent weed control whereas in imidazolinone and tribenuronmethyl 

tolerant sunflower varieties, imazamox and tribenuron-methyl can be effectively 

applied as post-emergence treatments without phytotoxicity on sunflower (Kazinczi et. al., 

2008). 

Legal regulations and measures taken in Hungary regarding Ambrosia artemisiifolia 

Two pieces of legislation address biological invasions in Hungary. One is the Convention 

on Biological Diversity, ratified in 1995, and the other is the Act on Nature Conservation 

(1996). Neither, however, provides directives for control. The agricultural administration in 

Hungary has legal measures to control weeds, but these regulations appear to be largely 

insufficient to avoid further invasion and expansion of certain species. The abundance of 

ragweed has been monitored at 410 locations within Budapest since 1994. Authority 

arrangements by Self-governments, inhabitants, Directorate of Plant Protection and Soil 

Conservation, civil organizations and State Medical Officer Services have already achieved 

considerable results in urban areas. Ten years ago, a countrywide anti-Ambrosia campaign 

was launched within the framework of the National Environmental Health Action Program. 

Hundreds of the 3600 Hungarian settlements introduced special regulations against A. 

artemisiifolia invasion. The campaign was supported by the Ministry of Welfare (Farkas et 

al., 1998). 

Since 1992, a regular monitoring of pollen concentration is done in Hungary. There is 

effective pollen predicting system since 2005, between May and September with the active 

work of 19 pollen traps in the country. 

Hungarian State Geological Institute and Institute for Land Measuring and Remote Sensing 

make the ragweed map of the country on the basis of the infested areas of the previous year, 

space photos, field surveys and other data. Before the beginning of the growing season, all of 

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the 19 Directorate of Plant and Soil Conservation in Hungary organize trainings for the field 

owners on the ecology, biology and control of A. artemisiifolia (Kacinczi et al., 2008). 

On the basis of plant protection laws, the protection against A. artemisiifolia is compulsory 

for the farmers until 30 th of June of each year. Since 2007, the prevention of the formation of 

flower-buds is required. In crops, general protection is recommended if the percentage (%) 

coverage of A. artemisiifolia exceeds 30. After 30 th of June, local checking of control is done 

by Field Officers (specialists) stationed in every large town. 

In 2004, an ―Ambrosia-free Interdepartmental Committee‖ was formed in Hungary, with 

the active support of 8 ministries. In 2007, self-governments together with the local civil 

organizations announced the ―Ambrosia-free House action‖, whose purpose is to reach 

Ambrosia-free surroundings by the active help of the civil organizations (Kacinczi et al., 

2008). 

Conclusions 

Invasion of Ambrosia artemisiifolia in Hungary deserves the attention of researchers, 

decision makers, policy formulators, opinion leaders and the public as well. Public interest 

focuses mainly on human health impacts of some allergenic species, but there is also some 

sensitivity to the degradation of natural values of protected and urban areas. However, the 

awareness of personal responsibility for preventing or controlling its invasion, and of its 

relation to land use practice, is very low. 


The authors thank the University of Pannonia, Georgikon Faculty and the European 

Environment Agency (EEA) for financial support and reviewers for their valuable comments 

and suggestions on the manuscript. 

References 

Assyov B, Dimitrov D & Vassilev R (2001) Conspecus of the Bulgarian vascular flora. Sofia, Bulgaria. 

Basky Zs (2007) The effect of indigenous aphids on the development of common ragweed (Ambrosia 

artemisiifolia L.) in Hungary. Hungarian Weed Research and Technology 8, 21-40. 

Bassett IJ & Crompton CW (1975) The Biology of Canadian weeds. 11. Ambrosia artemisiifolia L. and A. 

psilostachya D.C. Canadian Journal of Plant Science 55, 463-476. 

Béres I & Bìrñ K (1993) Life cycle and phenophases of common ragweed (Ambrosia elatior L.). Növényvédelem 

29, 148-151. 

Berés I & Hunyadi K (1980) The Biology of Ambrosia elatior L. Novenyvédelem 16, 109-116 (in Hungarian). 

Béres I (1981) A parlagfű (Ambrosia elatior L.) hazai elterjedése, biolñgiája és a védekezés lehetőségei). Ph.D 

dissertation. Keszthely, Hungary. 

Béres I & Hunyadi K (1991) Distribution of Ambrosia elatior in Hungary. (Az Ambrosia elatior elterjedése 

Magyarországon). Növényvédelem 27, 405-410. 

Béres I (2003) Distribution, importance and biology of common ragweed (Ambrosia artemisiifolia L.). 

Növényvédelem 39, 293-302. 

Bohren C (2006) Ambrosia artemisiifolia L.- in Switzerland: Concerted action to prevent further spreading, 

Nachrichtenbl. Deut. Pflanzenschutzd. 58(11), 304 – 308. 

Boros Á (1938) Floristical issues II. Bot. Közlem. 35, 310-320. 

Brückner D (2001) Allelopathy of common ragweed (Ambrosia artemisiifolia L.) – direct an indirect 

interactions. Ph.D dissertation. Keszthely: University of Pannonia. 

Comtois P (1998) Ragweed (Ambrosia sp.): The phoenix of allergophytes. – In: Ragweed in Europe. 6 th Int. 

Congr. Aerobiol., Perugia 1998. Satelite Symp. Proc. (ed. F. Th. M. Spieksma), pp. 3 – 5. – Alk – Abellñ 

A/S, Horsholm DK. 

Posters 


363

Corsico R, Falagiani P, Ariano R, Berra D, Biale C, Bonifazi F, Campi P, Feliziani V, Frenquelli G, Galimberti 

M, Gallesio M, Liccardi T & Loreti A (2000) An epidemiological survey on the allergological importance 

of some emerging pollens in Italy. J. Invest. Allergol. Clin. Immunol. 10, 155-161. 

Farkas I, Erdei E, Magyar D & Fehér Z (1998) Anti-ragweed campaign in Hungary in the frame of the National 

Health Action Programme. – Alk-Abell A/S p. 46. Horsholm DK - In: Ragweed in Europe. 6 th Int. Congr. 

Aerobiol., Perugia 1998. Satellite Symp. Proc. (ed. F. Th. M. Spieksma). 

Farr DF & Castlebury LA (2001) Septoria epambrosiae sp. nov. on Ambrosia artemisiifolia (common ragweed) 

Sydowia 53, 81-92. 

Geismann TA, Griffin S, Waddell TG & Chen HH (1969) Sesquiterpene lactones. Some new constituents of 

Ambrosia species: A. psilostachya and A. acanthicarpa. Phytochemistry 8, 145-150. 

Goeden RD & Teerink JA (1993) Phytophagous insect faunas of Dicoria canescens and Iva axillaris, native 

relatives of ragweeds, Ambrosia spp., in Southern California, with analyses of insect associates of 

Ambrosiinae. Annals of the Entomological Society of America 86, 38-50. 

Gudzinska Z (1993) Genus Ambrosia (Asteraceae) in Lithuania. Thaiszia 3, 89-96. 

Hartmann F, Hoffmanné P & Tñth C (2003) Distribution of atrazine-resistant biotypes of common ragweed 

(Ambrosia artemisiifolia L.) in Hungary. Növényvédelem 39, 313-318. 

Héjjas I & Borhidi A (1960) Flora of Csurgñ and surroundings. Bot. Közlem. 48, 245-256. 

Hjorth N, Roed-Petersen J & Thomsen K (1976) Airborne contact dermatitis from Compositae oleoresins 

simulating photodermatitis. British J. Dermatol. 95, 613-620. 

Hsu LM (2005) Seed germination and chemical control of common ragweed (Ambrosia artemisiifolia). Plant 

Prot. Bull. 47, 361-370 

Járai-Komlñdi M (1998) Ragweed in Hungary. In: Ragweed in Europe. 6 th Int. Congr. Aerobiol., Perugia 1998. 

Satelite Symp. Proc. (ed. F. Th. M. Spieksma), pp. 33 – 38. – Alk – Abellñ A/S, Horsholm DK. 

Járainé M (2003) Pannon Encyclopedy. Flora of Hungary. Budapest: Urbris Könyvkiadñ. 

Juhász L (1963) Ambrosia species in Hungary. Egri Tanárk. Főisk. Tud. Közl. 1, 225-227. 

Juhász M (1995) New results of aeropalynological research in Southern Hungary. Hungarian Acad. Sci. Reg. 

Comm. (Szeged) Publ. 5, 17 – 30 (In Hungarian). 

Kazinczi G, Rñbert N, Pathy Z, Béres I & Bìrñ K (2008) Common ragweed (Ambrosia artemisiifolia l.): A 

review with special regards to the results in Hungary. Herbologia Vol. 9, No. 1. 58-147 

Kiss L, Vajna L & Bohár GY (2001) Mysterious disease of common ragweed. Élet és Tudomány 32, 1012-1014. 

Kiss L, Vajna L & Bohár GY (2003) Biological control of common ragweed (Ambrosia artemisiifolia L.). 

Növényvédelem 39, 319-331. 

Kiss L & Béres I (2006) Anthropogenic factors behind the recent population expansion of common ragweed 

(Ambrosia artemisiifolia) in Eastern Europe: is there a correlation with politial transitions? J. Biogeogr. 

33, 2156-2157. 

Kőmìves T, Béres I & Reisinger P (2006) New strategy of the integrated protetion against common ragweed 

(Ambrosia artemisiifolia L). Hung. Weed Res. and Technol. 6, 5-50. 

Kovaţeviţ J & Miller S (1958) Ambrosia artemisiifolia in Jugoslawien. Mitteil. Internat. Vereinigung für 

Samenkontrolle 23, 355-360. 

Lengyel G (1923) The occurrence of Ambrosia artemisiifolia L. in Hungary. Bot. Közlem. 21, 100. 

Makra L, Juhász M, Borsos E & Béczi R (2004) Meteorological variables connected with airbone ragweed 

pollen in Southern Hungary. – Int. J. Biometerol. 49, 37 – 49. 

Makra L, Juhász M, Rita B & Borsos E (2005) 'The history and impacts of airborne Ambrosia (Asteraceae) 

pollen in Hungary', Grana 44(1), 57 – 64. 

Malkiewicz M & Wasowicz A (2003) Ambrosia pollen grains in aeroplancton of Wroclaw. Horticultura 13, 333- 

339. 

Maupin P & Apparicio P (2004) Relationships between Ambrosia artemisiifolia sites and the physical and social 

environments of Montreal (Canada). IEEE IGARSS 2004, Anchorage (Alaska), September 2004, 4 p. 

Milanova S & Nakova R (2002) Some morphological and bioecological characteristics of Ambrosia 

artemisiifolia L. Herbologia 3, 113-120. 

Moesz G (1926) The occurrence of several new interesting plants. Bot. Közlem. 23, 184-186. 

Rybnicek O & Jager S (2001) Ambrosia (ragweed) in Europe. Allergy Clin. Immunol. Int. 13, 60-66. 

Soñ R (1970) Taxonomical and Plant Geographical Handbook of Hungarian Flora and Vegetation. IV. Budapest: 

Akadémiai Kiadñ. 

Szentey L, Tñth Á & Dancza I (2004) Ambrosia-free Hungary is our common interest. Plant and Soil Protection 

Central Service, Budapest, Hungary. 

Szigetvári CS & Benkő ZS (2004) Ürömlevelű parlagfű (Ambrosia artemisiifolia L.). Pages 337-370 in B. 

Mihály and Z. Botta-Dukát, eds. Biological Invasions in Hungary. Invasive Alien Plants. Budapest: 

Természetbúvár Alapìtvány Kiadñ. 

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Takács A, Horváth J & Mikulás J (2004) Inhibitory effect of Chelidonium majus extracts. Z. Pflanzenk. 

Pflanzen, Sonderh. 19, 285-292. 

Taramarcaz P, Lambelet C, Clot B, Keimer C & Hauser C (2005) Ragweed (Ambrosia) progression and its 

health risks: will Switzerland resist this invasion? SWISS MED WKLY 135, 538–548. 

Timár L (1955) A noxious weed in Szeged. Dél-Magyarország, Szeged, 18th Jan, 1955. 

Toole EH, Brown E (1946) Final results of Duriel buried seed experiment. Journal of Agricultural Research 72, 

201-210. 

Tñth Á, Hoffmanné & Szentey L (2004). Ambrosia situation in Hungary in 2003. Difficulties of pollen reduction 

in the air. 50th Plant Protection Scientific Days. Budapest, Hungary. p.69. 

Tñth A, Benécs-Bárdi G & Balázs Gy (1999) Results of national weed surveys in arable land during the past 50 

years in Hungary. Proceedings of the Crop Protection Conference, Brighton, pp 805–810. British Crop 

Protection Council, London. 

Ujvárosi M (1973) Weed control. Budapest, Hungary. 288p 

Vysokopoyasnyi AI (2004) Plant quarantine in Kuban. Zash. Kar. Rast. 5, 12-14. 

Wareing, PF (1975) Endogenous inhibitors on seed germination and dormancy. In: W. Ruhland (ed.), 

Encyclopedia of Plant Physiology. Springer-Verlag, Berlin. pp.909-924 

Wittenberg R (Ed.) (2005) An inventory of alien species and their threat to biodiversity and economy in 

Switzerland. CABI Bioscience Switzerland Centre report to the Swiss Agency for Environment, Forests 

and Landscape. 

Wopfner N, Gadermaier G, Egger M, Asero R, Ebner C, Jahn-Schmid B & Ferreira F (2005) The Spectrum of 

Allergens in Ragweed and Mugwort Pollen. Int Arch Allergy Immunol 138, 337–346. 

Zapolovski SA, Derecha AA, Dazhuk MA & Rybalchenko, SL (2004) Common ragweed in the Zhitomir region. 

Zashchita i Karantin Rasteniì 11, 38-39. 

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Heracleum sosnowskyi invasion in Lithuania 

L. Baleţentiene 

Lithuanian University of Agriculture, Lithuanian University of Agriculture, Studentu 11, 

Akademija LT-53361, Kaunas dist. Lithuania. E-mail: ligitaba@gmail.com 

Introduction 

Heracleum sosnowskyi is among the 6 most dangerous invasive species that 

spread along roadsides and naturalized in Lithuanian habitats. This species 

outcompetes with native autochthones species, thus changing community 

composition and structure. Habitat assessments of the establishment and 

abundances of H. sosnowskyi in native plant communities at an individual 

location scale were carried out in Lithuania. Eight locations (10 m 2 each) 

distributed in a 6 km transect along the highway Via Baltica near Kaunas, in 

the centre of Lithuania, were inventoried for the establishment and 

abundance of H. sosnowskyi. Four H. sosnowskyi population types were 

found: 1) individuals or small groups of 1-2 fruited individuals; 2) groups of 

n×10 m; 3) strips of 1-10 m width and different lengths along forests, roads, 

Nemunas river banks; and 4) large pure colonies consisting of nx10 

individuals in 10 m 2 and with relative coverage of 60-80% or even 100%. 

Species‘ abundance was structured according to the distance from highways 

and significantly correlated (r=0.7) with native plant community type. H. 

sosnowskyi find opportunities for colonization and reproduction resulting in 

decrease of natural diversity in areas where established. Species invasion 

success was highest in roadsides (12.3%), abandoned grasslands (6.7%), and 

wastelands (2.4%). 

Increasing human activity and transportation have resulted in a concomitant increase of 

alien plant spread into new countries and habitats worldwide (Gulezian & Nyberg, 2010; 

Landis, 2004; Miller et al., 2010). 

Several species of the genus Heracleum (Apiaceae) were introduced into Europe from 

south-west Asia in the 19 th century and are now widespread in many countries (Jahodová et 

al., 2007). Heracleum sosnowskyi Mand. (cow parsnip, Sosnovski hogweed) is one of those 

introduced species and it is considered highly invasive due to its threat to native species, 

biodiversity and ecosystems in the EPPO region (Giant Alien Project, 2005; EPPO List of 

invasive alien plants, 2006) and in Lithuania (List of invasive organisms in Lithuania, 2009). 

In particular, in Lithuania Heracleum sosnowskyi is an invasive tall forb listed among the 

six most dangerous invasive alien species that spread across roadsides, natural riparian zones 

and forest edge habitats in Lithuania (Order No D1-663, 2009), where it changes community 

composition and structure and landscape. H. sosnowskyi outcompetes with native species and 

changes the composition as well as the structure of plant communities due to its high 

competition characteristics. H. sosnowskyi is native to the Caucasus where it occurs in the 

upper forest belt of the southern slopes, mainly in meadows, clearings and forest edges 

(Nielsen et al., 2005). This species was originally described as a separate species by I. 

Mandenova in 1944 (Lapiņš et al. 2002; Oboļeviţa, 2001). It was promoted as a crop in 

northwest Russia, where it was first introduced in 1947. From the 1940s onwards, it was 

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366

introduced as a potential forage crop in Latvia, Estonia, Lithuania, Belarus, Ukraine and the 

former German Democratic Republic (Nielsen et al., 2005). Initially H. sosnowskyi was 

introduced as a fodder plant in the sixth decade of the last century at Research Station of 

Lithuanian University of Agriculture (Krikšţikas, 1970 unpubl.). The species therefore has 

been probably spread over Lithuania through several independent introductions: formerly 

escape from cultivation, it is now currently spreading from roadside (Gudzinskas, 1998; SGP, 

2005). 

H. sosnowskyi is able to form pure stands and to change ecosystems diversity by outcompeting 

autochthones species in native habitats thus making huge damage to native flora 

and landscapes. Since plant competition is mainly for access to light, plants that grow higher 

biomass create negative feedback in the form of more self shading and shading of its 

neighbors (Finnoff & Tschirhart, 2009; Kowarik, 2003). It establishes in the following 

habitats: pastures, river banks, roadsides and rail networks, and wastelands (Pimentel et al., 

2005). 

Responding to one of the greatest EU goals to prevent biodiversity degradation up to 2010, 

effective measures to choke off the spread of H. sosnowskyi in Lithuanian natural grassland 

and forest habitats need to be established. The objective of this article is to assess the impacts 

of H. sosnowskyi on native habitats in Lithuania and to record the distribution and abundance 

of the species in the most heavily invaded habitat types. 


H. sosnowskyi and other allied species belong to Heracleum sect. Pubescentia (H. 

pubescens, H. mantegazzianum, H. sosnowskyi and H. sommieri). The distribution of this 

group covers nearly all Europe except the arctic, Mediterranean regions, the temperate zone of 

Asia and North America (Weber, 2003). 

Table 1 - Assessed habitat and other land-cover types 

Habitat type Key traits 

Abandoned More or less nutrient rich sites which have not been subject to regular 

grasslands 

land use in recent years 

Open riverbanks Unshaded riverbanks with herbaceous vegetation 

Open roadsides Unshaded 

vegetation 

roadsides (verges, embankments) with herbaceous 

Wastelands Heavily disturbed sites, such as sand pits etc. 

Forest edge Ecotonal zone between forest and adjacent vegetation and the 

outermost 10m of the forest itself 

Housing areas Areas of coherent plots used for housing 

The type of H. sosnowskyi impact (i.e., ecological, socio-economic or human health) was 

determined through literature review (Nielsen et al., 2005; Oboļeviţa, 2001). 

Lithuania lies in the very Centre of Europe on the Baltic sea and houses a temperate 

climate with 660 mm precipitation (Olenin, 2002), 17þC and 4þC summer and winter mean 

temperature respectively. A plant data set (6 km × 10 km area) was pre-selected for screening 

in the central part of Lithuania, near the intensive traffic highway ‗Via Baltica‘. The invasion 

degree (%) of H. sosnowskyi was defined as the ratio between the area of species stands and 

the total area of the respective habitat type (as indicated in Table 1) within the study areas 

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(Thiele & Otte, 2008). Habitat saturation was defined as the ratio of the area covered by H. 

sosnowskyi within the stands and the total area of the habitat type (Pyśek & Pyśek, 1995). 

Data of H. sosnowskyi invasion regional patterns were used to create a ranking of invasion 

intensity by summing up weights allocated to estimated frequency classes and maximum 

stand sizes, with higher frequencies and larger stand sizes receiving higher weights. Both 

published and unpublished floristic data were analyzed. The alien plant was ranked as a 

transformer using the categories of the Richardson et al. (2000) classification system. 

Results and Discussion 

H. sosnowskyi has great competition facilities due to its giant size and high reproductivity: 

a mature plant has pinnately divided leaves of 1 m in size, a hollow flowering stem up to 

height with 3 m (up to 4.5 m) tall regrowing in spring from the large fleshy tap root, stem 

diameter in basal part is 12-15 cm, the main inflorescence has a diameter up to 0.5 m and 

produces over 8000 fruits. This monocarpic perennial plant is resistant to cutting and fire. 

During the 1 st year, a plant grows rather heavily and starts to grow intensively in the 2 nd and 

3 rd years, bringing up only basal leaves. Having accumulated appropriate amounts of 

resources needed for flowering, the plant matures on the years 4–5 (6–9 or 12–13 in 

unfavourable conditions). The plant flowers in June-July (August-October) with total seed 

production range from 10,000 to 100,000 (Table 2). Approximately a half of this amount of 

seeds produces the main inflorescence. The plant does not spread vegetatively, but is reported 

to live up to 6 years when planted for biomass and silage production (Satsyperova, 1984). 

Table 2 - H. sosnowskyi life stages in Lithuania 

Life stage Date 

Germination April-September 

Seedlings 1st vegetation season 

Leaf clusters (rosette plants) each year (for 2-5 years) until the plant flowers 

Maturity on the year 4–5 (6–9 or 12–13 year in unfavorable conditions) 

Flowering June-July (after cutting – in August-October) 

Seeds producing August-September 

As many invasive alien species (Wadsworth et al., 2000), H. sosnowskyi generally spreads 

from roads and establishes the largest populations in wastelands, rangelands, along roadsides, 

but also penetrates in semi natural and natural habitats (slopes, meadows, river banks, forest 

edges) (Fig. 1). Mean linear speed of this species was estimated 10 m per year in Lithuania 

(Gudzinskas & Rasomavicius, 2005). As was observed on slopes along a roadside near 

Kaunas, this invader spread over 600 m during 2000-2010 or may therefore colonize suitable 

neighbour habitats with average linear speed of 60 m per year. It can be noted that the 

observed linear speed is higher than that reported by former authors. Such robust spread of H. 

sosnowskyi is mostly determined by certain advantageous biological characteristics: intensive 

light competition due to giant height and diameter (3 m); high seed germination (78%±0.15) 

and seedling growth in early spring before the start of other plants; high survival of juvenile 

individuals; just 1 seedling is able to proceed a new invasion; high seed production and 

intensive short-distance seed spread (>10 m/yr). Establishing in new territories a plant can 

form different size and density populations; developed plantations (0.5 ha) expand 1200 m -2 

per year. 

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Figure 1 - Successional scheme of H. sosnowskyi colonies 

These plant peculiarities resulted in its successfull spread over all Lithuanian territory during 

20-30 years (Fig. 2). 

1990 

2005 

Meadow 

Wasteland 

River bank 

Forest edge 

H. 

sosnowskyi 

Population of 

H. sosnowskyi 

Figure 2 - Distribution of H. sosnowskyi 

during five years in Lithuania (Gudzinskas & 

Rasomavicius, 2005) 

Unemployed 

Tree and bush 

Succesional 

communities with 

H. sosnowskyi 

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Depending on environmental conditions and population age H. sosnowskyi forms populations 

of different type and size which area covers from several m 2 to several ha includes several 

hundred matured fructiferous individuals (Table 3). 

Table 3 - Population types of H. sosnowskyi in Lithuania 

Population 

type 

Solitary 

individuals 

Groups of 

individuals 

Habitat type Area Fructiferous 

individual in 

Roadside, abandoned 

grassland, forests, 

housing areas 


grassland, forests 

Strips Along river banks, 

forests edge, roadside 

Large pure 

colonies 


grassland, wastelands 

10 m -2 

Density 

(plant 10 m - 

Coverage 

(%) 

2 

) 

n × m 2 1-2 1-3 5-10 

1- 10 m 2 1-3 3-8 20- 30 

1-10 m 

width × 

n×10-100 m 

length 

1-3 - n × 10 2-8- n × 10 10-30 

n × 10-100 1-3 (20) – n × 

10-1000 

individuals 

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60-80% 

(100%) 

H. sosnowskyi successfully passed habitats filters demonstrating high ecologic plasticity and 

invasiveness extent penetrating in anthropogenized, semi natural and natural communities (Kolar 

& Lodge, 2001; Landis, 2003). This species had spread in 17 administrative districts until 1990 

and was registered in all regions of Lithuania over an area of 100 km 2 in 2005 (Gudzinskas & 

Rasomavicius, 2005). 80 % of H. sosnowskyi colonies were established in anthropogenized areas: 

wastelands, roadsides and housing areas, and only 20% of colonies penetrated in natural habitats: 

forests and their edges (about 0.2 km 2 ), riverbanks, meadows etc. The most evident floristical 

changes occurred in pine forest (Vaccinio-Pinetum) habitats: specific mosses to these forests 

(Pleurozium schreberi, Ptilium crista-castrensis) changed into species found in deciduous and 

mixed forests (Plagomnium undulatum, Eurlynchium angustirete, Atrichum undulatum). H. 

sosnowskyi transformed plant communities of forest edges resulting in the establishment of 

spring ephemerides (Ficaria verna, Pulmonaria obscura), shade-tolerant (Geum rivale, 

Glechoma hederacea, Lysimachia nummularia) and ruderal (Anthriscus sylvestris, Cirsium 

arvense, Urtica dioica) species (Table 4). 

Hogweed stressed native communities changing their structure and composition. Hogweed 

pushed out indigenous species, only some shade tolerant plants remained, landscape consequently 

lose their original habitats (Finnoff & Tschirhart, 2009). Such an aggressive invader that change 

character, condition, form or nature of ecosystems over substantial areas may be named 

‗transformers‘ (Richardson et al., 2000, Pyśek et al., 2004; Weber, 2003). 

Significantly (r=0.7) the highest invasion percentage (12.3%) was found in open roadsides and 

was followed by abandoned grasslands (6.70%), wasteland areas (2.40%), and open riverbanks 

(1.20%) (Fig. 3). Invasion percentages of less than 1% were observed in the remaining invaded 

habitat types. 

370

Table 4 - Frequency (%) of constant species in different communities with H.sosnowskyi 

Constant species Grass communities Bush communities Tree communities 

Urtica dioica 71.5±0.14 88.6±0.15 74.9±0.23 

Anthriscus sylvestris 

Artemisia vulgaris 

Cirsium arvense 

Dactylis glomerata 

Festuca pratensis 

Salix caprea 

Frangula alnus 

Alnus incana 

Geum rivale 

Lysimachia nummularia 

Chelidonium majus 

Eurhynchium angustirete 

Acer platanoides 

Padus avium 

Plagomnium undulatum 

Open 

roadsides 

12.30% 

Wastleands 

2.40% 

51.9±0.11 

80.9±0.13 

56.9±0.10 

76.2±0.20 

77.1±0.18 

Forest edge 

0.30% 

66.5±0.21 

55.7±0.14 

55.7±0.11 

44.5±0.21 

44.7±0.12 

25.3±0.10 

26.1±0,12 

Housing areas 

0.01% 

Abandoned 

grasslands 

6.70% 

Open 

riverbanks 

1.20% 

Figure 3 - Invasion (%) of H. sosnowskyi in different habitat 

Conclusions 

75.0±0.18 

75.1±0.11 

65.4±0.20 

62.5±0.12 

62.5±0.15 

62.4±0.19 

62.4±0.20 

62.4±0.14 

Highway roadsides represent the main invasion corridor of H. sosnowskyi in Lithuania. 

Because the rapidly increasing H. sosnowskyi has significant negative consequences for both 

human enterprise (Nielsen et al., 2005) and native ecological systems, there is a pressing need to 

mitigate the impacts of this species by finding effective control measures. Evaluation of this 

invasive alien plant representing an ecological risk is an initiating task for future studies at the 

national level. Analyses covering larger area are also necessary. 

References 

Finnoff D & Tschirhart J (2009) Plant competition and exclusion with optimizing individuals. Journal of Theoretical 

Biology 261(2), 227-37. 

Giant Alien Project (2002-2005). European Commission, 5th Framework Programme, Energy, Environment and 

Sustainable Development‘, project no. EVK2-CT-2001-00128 

Posters 


371

Gudzinskas Z & Rasomavicius V (2005) Communities and habitat preferences of Heracleum sosnowskyi in 

Lithuania. In The Ecology and Management of the Giant Alien Heracleum mantegazzianum. Final 

International Workshop of the ‗Giant Alien‘ Project. Justus–Liebig–University Giessen. Division of 

Landscape Ecology and Landscape Planning. Germany, 21. 

Gudzinskas Z (1998) Conspectus of alien plant species of Lithuania. 7. Apiaceae, Apocynaceae, Asclepiadaceae, 

Caprifoliaceae, Dipsacaceae, Oleaceae,Sambucaceae, Viburnaceae, and Valerianaceae. Botanica Lithuanica 

4(3), 249-265. 

Gulezian PZ & Nyberg DW (2010) Distribution of invasive plants in a spatially structured urban landscape. 

Landscape Urban Planning doi:10.1016/j.landurbplan. 2009.12.013 (in press) 

Jahodová S, Trybush S, Pysek P, Wade M & Karp A (2007) Invasive species of Heracleum in Europe: an insight into 

genetic relationships and invasion history. Diversity and Distributions 13, 99–114. 

Kolar CS & Lodge DM (2001) Progress in invasion biology: Predicting invaders. Trends in Ecology & Evolution 16, 

199–204. 

Kowarik I (2003) Biologische invasionen: Neophyten und Neozoen in Mitteleuropa. Stuttgart: Ulmer [in German]. 

Landis WG (2003) Ecological risk assessment conceptual model formulation for nonindigenous species. Risk 

Analysis 24, 847–858. 

Lapiņš D, Bērziņš A, Gavrilova Ģ, Riekstiņš A, Karpenskis G, Narvils M, Runce A, Liguts V & Stašinskis R (2002) 

[Hogweed, bringing their spread under control. Provisional recommendations.] LLKC, Ozolnieki, 28. (in 

Latvian) 

[List of invasive organisms in Lithuania] Order No D1-663, 09 11 2009, LT Minister of Environment. [State News], 

2009, Nr.: 135 -5904. 

Mack RN, Simberloff D, Lonsdale WM, Evans H, Clout M, & Bazzaz FA (2000) Biotic invasions: Causes, 

epidemiology, global consequences and control. Ecological Applications 10, 689–710. 

Miller TK, Allen C R, Landis WG & Merchant J W (2010) Risk assessment: Simultaneously prioritizing the control 

of invasive plant species and the conservation of rare plant species. Biology of Conservation 

doi:10.1016/j.biocon.2010.05.015. (in press) 

Mooney HA & Hobbs RJ (2000). Invasive species changing world. Washington, DC: Island Press. 

Morse LE, Randall JM, Benton N, Hiebert R & Lu S (2004) An Invasive Species Assessment Protocol: Evaluating 

Non-native Plants for their Impact on Biodiversity. Version 1. Nature Serve, Arlington, VA, USA. 

Nielsen C, Ravn HP, Nentwig W & Wade PM (eds.) (2005) The Giant Hogweed Best Practice Manual. Guidelines 

for the management and control of an invasive weed in Europe. Forest & Landscape Denmark, Hørsholm, 44. 

Oboļeviţa D (2001) [Hogweed and its distribution in Latvia] LLKC, Ozolnieki (in Latvian 

Olenin S (2002) Black Sea - Baltic Sea invasion corridors. In: Alien marine organisms introduced by ships in the 

Mediterranean and Black Seas. CIESM Workshops 

Pimentel D, Zuniga R, & Morrison D (2005) Update on the environmental and economic costs associated with alieninvasive 

species in the United States. Ecological Economics 52, 273–288. 

Pyśek P & Pyśek A (1995) Invasion by Heracleum mantegazzianum in different habitats in the Czech Republic. 

Journal of Vegetation Science 6, 711–718. 

Pyśek P, Richardson D M, Rejmánek M, Webster G, Williamson M & Kirschner J (2004) Alien plants in checklists 

and floras: towards better communication between taxonomists and ecologists. Taxon 53, 131-143. 

Rejmánek M, Richardson DM, Higgins SI, Pitcairn MJ & Grotkopp E (2005) Ecology of invasive plants: state of the 

art. Invasive alien species: searching for solutions (ed. by Mooney HA, Mack RM, McNeely JA, Neville L, 

Schei P & Waage J), 104–161. Island Press, Washington, D.C. 

Richardson DM, Allsopp N, D‘Antonio CM, Milton SJ & Rejmánek M (2000) Plant invasions - the role of 

mutualisms. Biological Reviews 75, 65–93. 

Satsyperova IF (1984) Hogweeds in the Flora of the USSR: New Forage Plants. Nauka, Leningrad. (In Russian) 

SGP (2005) Removal of Invasive Specie Sosnowski's Cow Parsnip in Marijampole County LIT/05/15. 

Thiele J & Otte A (2008) Invasion patterns of Heracleum mantegazzianum in Germany on the regional and 

landscape scales. Journal for Nature Conservation 16, 61–71. 

Wadsworth RA, Collingham YC, Willis SG, Huntley B & Hulme PE (2000) Simulating the spread and management 

of alien riparian weeds: are they out of control? Journal of Applied Ecology 37, 28–38. 

Weber E (2003) Invasive plant species of the world a reference guide to environmental weeds. CABI Publishing, 

Wallingford. 

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372

Distribution of silverleaf nightshade (Solanum elaeagnifolium) in Greece and invasiveness 

as related to leaf morphological characters 

Garifalia Economou 1 , Costas Fasseas 2 , D. Christodoulakis 3 & Ilias S. Travlos 1 

1 Laboratory of Agronomy, 2 Laboratory of Electron Microscopy 

E-mail: economou@aua.gr, cagr2ecg@noc.aua.gr 

2 Agricultural University of Athens, Iera Odos 75, Athens 11855, Hellas 

3 Department of Botany, Faculty of Biology, University of Athens, 15701, Hellas 

Solanum elaeagnifolium is a noxious and invasive alien weed, against which international 

measures have to be taken in many areas, according to EPPO guidelines. It has been introduced 

from America to Europe, Africa, Asia and Australia, and in many cases it is considered as an 

important weed of croplands and pastures, mostly in cultivated land, disturbed areas, overgrazed 

areas, canal banks and human environments. In Greece, this invasive species causes major 

economic impacts related to its prevention, control and eradication (e.g. damage to crops, 

damages in urban areas, congestion in waterways, etc.). According to surveys undertaken during 

the last three years across the main cultivated zone in Greece, S. elaeagnifolium was found 

locally naturalised, it rapidly expands its habitat, progressively becoming a weed of agronomic 

importance. Currently, it exhibits an adaptation to a great variation of abiotic factors within its 

dispersal in Greek agroecosystems showing a particular preference in regions with low annual 

rainfall. According to our preliminary field experiment the occurrence of silverleaf nightshade in 

corn resulted in a maximum grain yield loss ranging from 14 to 47% for early emerging weed 

plants and less than 7% yield loss when the weed seedlings occurred later than the V4 corn 

growth stage. From this point of view, silverleaf nightshade obtains an emerging competitiveness 

in corn crop inducing the need of taking measures to prevent its potential introduction in other 

arable crops. The invasiveness of this weed is known to be aggravated by high seed production 

and an extensive root system that promotes vegetative multiplication, one of the main 

components making its control ineffective. It is widely known that the application of 

conventional weed control methods proved inadequate to prevent the rapid dispersal to a variety 

of habitats. Taking into account the role of leaf morphology, in terms of the ineffective control by 

means of foliage herbicides, the usual control strategy, we studied the leaf structure. Several 

morphological traits such as amphistomaty, abundance of palisade tissue, and hairs give an 

additional advantage to S. elaeagnifolium under the stressful Mediterranean conditions and 

significantly contribute to its noticeable invasiveness. 

The study of the silverleaf nightshade‘s leaf morphology may help the future investigations on 

minimizing the negative impact of herbicides use and improving the control measures. 

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373

Germination ecology of the invasive Acacia saligna (Fabaceae) in Sardinia: interpopulation 

variability and effects of temperature and salinity 

F Meloni*, CA Dettori*, F Mascia*, L Podda**, G Bacchetta* 

*Centro Conservazione Biodiversità (CCB), Department of Botanical Sciences, University of 

Cagliari, Viale Sant’Ignazio 13, 09123 Cagliari (Italy), E-mail: info@ccb-sardegna.it 

**CRITERIA S.r.l. via Cugia 14, 09129 Cagliari (Italy). E-mail: l.podda@criteriaweb.it 

Introduction 

Acacia saligna (Labill.) Wendl. (Fabaceae) is a phanerophyte native to 

Australia. It was introduced in Sardinia for afforestation, mainly in coastal 

areas, and at present it is considered as naturalized, becoming invasive in sand 

dune habitats. In this work germination tests were carried out at the Sardinian 

Germplasm Bank (BG-SAR), testing different temperatures and percentages of 

NaCl, on seeds belonging to five accessions from four populations, in order to 

obtain data concerning the potential invasiveness of A. saligna, with particular 

attention to coastland habitats. The optimal temperature range for seed 

germination of all populations of A. saligna was 15-20þC; salt concentration 

increase influenced the germinative capacity causing a decrease in final 

percentages. At 1% of NaCl concentration the germination fell remarkably, 

final values stayed rather high only at 15þC, being nearly always above 50%. At 

2% of NaCl concentration final germination percentages was relatively low 

(below 40%) and it occurred almost only at 15þC. The work is intended to 

represent a contribute to the knowledge of the seed ecology and germination 

behavior of the species, also providing new data on the interpopulation and 

interannual variability, and relating them with the invasion dynamics of A. 

saligna in the coastland habitats of the island. 

Acacia saligna (Labill.) H.L. Wendl. (Fabaceae) is a phanerophyte native to Australia. It 

forms a dense shrub, usually 2–5 m tall that may grow treelike to 8 m tall with a single main stem 

whose diameter can reach up to 30 cm. The species does not withstand frost and grows better 

where the winter and summer mean temperatures are 13þC and 30þC respectively (NAS, 1980). It 

can therefore live throughout the tropical and warm temperate regions of the world, mainly on 

sandy, coastal plains, but it can also be found in a wide range of habitats, from swampy sites and 

riverbanks to rocky hills and coastal slopes (Groves, 1994). As noted by Doran & Turnbull 

(1997) it occurs on many soil types, especially poor and calcareous sands, but also on moderately 

heavy clays, while Simmons (1987) reported that it is tolerant to alkaline and saline soils. This 

tolerance to many different substrates even with low level of nutrients, together with an early 

reproductive maturity, a large seed production and the ability of seeds to survive fire, contributed 

to turn A. saligna into an invasive species outside its natural range (Cronk & Fuller, 1995). At 

present it is considered invasive in Chile, Cyprus, South Africa and, as regards Europe, in Spain, 

Portugal and Italy. 

In the Cape floristic region of South Africa, where it appears to alter N-cycling regimes 

through long-term invasions, it is regarded as one of the most important invasive alien plants 

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374

(Henderson, 2001). The main impacts that the invasive acacias have in natural and semi-natural 

ecosystems in this region include changes in plant community structure, increased flammability 

(Van Wilgen & Richardson, 1985) and modifications in the soil chemistry leading, among other 

things, to increased invasion by alien species (Richardson et al., 2000). Furthermore dense stands 

lead to reduced native species diversity (Richardson et al., 1989). In riparian habitats, dense 

formations of A. saligna transform native communities with marked alteration of ecosystem 

functioning (Holmes et al., 2005) and in coastal habitats they naturally stabilize mobile sand 

dunes, altering coastal sediment movement and leading to extensive beach erosion (Lubke, 1985). 

It also infests water courses (sometimes decreasing the water availability for irrigation), and has 

proved to be difficult to eradicate (NAS, 1980). 

Acacia saligna is a neophyte in Europe, and one of the forestry species introduced for 

restoration of damaged areas (Vilà et al., 2008). It was introduced in Sardinia in the 1950s for 

afforestation (Aru, 1967; Mayer, 1995) and at present it is commonly recorded as naturalized 

(Bacchetta, 2006; Bocchieri & Iiriti, 2003; Conti et al., 2005; Fenu & Bacchetta, 2008) or 

invasive (Brundu et al., 2004; Camarda et al., 2002; Podda et al., 2010) in coastal habitats and 

mainly in sand dunes (Bacchetta et al., 2009). This is confirmed by the recent national inventory 

of the Italian non-native flora by Celesti-Grapow et al. (2009), in which A. saligna is listed as 

invasive in Basilicata, Calabria and Sardinia. In other Italian regions it is reported as naturalized 

(Apulia, Campania, Sicily and Tuscany), while it is only casual in Liguria and Molise. 

One of the factors that may have a strong influence on A. saligna invasiveness is the great 

profusion of seeds; in fact Richardson & Kluge (2008) report the annual seed rain of A. saligna 

measured on the ground, recorded as 5,443 seeds per m², producing a soil seed bank with a 

density of seeds of about 46,000 per m². About 2–8% of the seeds can germinate immediately 

(Milton & Hall, 1981), while the vast majority of the seeds are added to the soil seed bank where 

they remain dormant but viable for more than 50 years until the seed coat is sufficiently damaged 

to be permeable to water and germinate (Milton & Hall, 1981). Only recently (Richardson & 

Kluge, 2008) the right attention has been given to understanding the role of soil seed banks in the 

invasiveness and long-term persistence of populations, concluding that the reduction of the soil 

seed bank is crucial. 

According to Baskin & Baskin (1998, 2004), A. saligna shows physical dormancy (PY), based 

on the structure and impermeability of the seed coat. A marked variation among seeds is pointed 

out as far as the toughness of the seed coat is concerned (Piotto & Di Noi, 2003); this feature 

enables the formation of soil seed banks so that germination occurs over a long period. 

Furthermore the seeds are fire adapted with an elaiosome that predisposes them to vertical 

dispersal into the soil by ants (Richardson & Kluge, 2008). 

In order to surmount dormancy and induce germination in A. saligna, Aref (2000) applied 

different pre-treatments, consisting in soaking the seeds in boiling water for different durations. 

Seeds without pre-treatment only reached 1.92% of germination and also after treatments with 

soaking the final germination percentage remained under 5%. The best result (32.05%) was 

obtained by placing seeds in boiling water. The recommended protocol by ISTA (2006) for the 

genus Acacia consists in chipping/filing/piercing the seeds and then soaking them for 3 hours. 

Piotto & Di Noi (2003) undermine the integrity of the seed coats by soaking the seeds in water at 

a high temperature for 12-24 hours or, alternatively, by chemical or mechanical scarification 

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375

(with sandpaper) and then soaking in water. The Seed Information Database (Liu et al., 2008) 

reports a final germination percentage of 96%, obtained after mechanical scarification (chipping 

with scalpel) in agar 1% with a photoperiod 12/12 at 21þC; 100% was reached in the same 

conditions but with a photoperiod 8/16 at 20þC. 

The aims of the present work are to investigate the seed germination behavior of A. saligna, 

with particular attention to the poorly previously investigated interpopulation and interannual 

variability (testing fresh and dry seeds), and the effects of temperature and salinity, in order to 

assess the potential invasiveness of the species in coastal habitats. 

Materials and methods 

Populations data and seed collection 

Four populations of Acacia saligna located in Southern Sardinia (Figure 1) were investigated 

(Table 1). Acacia saligna VIL, MAS and TEU populations grow on coastal sands originated 

principally from granites, living therefore on a saline substrate with NaCl from marine spray and 

layer. CAG population occupies clays on a limestone hill, with different salts. VIL population has 

been monitored since 2008 through the placement of study plots (75 m 2 ) in stabilized dunal zone 

in order to check the invasive behavior of the species (Podda et al., 2009). Preliminary results of 

the monitoring are put in connection with the results of this study. 

Seeds were harvested at the time of natural ripening and dispersal from about 20% of the 

reproducers among total individuals, according to criteria that guarantee a high quality and 

representativeness of the collected material (Guarino et al., 1995). Seeds were manually removed 

from pods and stored at the Sardinian Germplasm Bank (BG-SAR), where they were placed in 

the dry room at 15% R.H. and 15þC (for the accessions collected in 2008) or immediately 

subjected to germination trials (as in the case of all the accessions collected in 2009). 

Figure 1 - Studied populations of Acacia saligna in Southern Sardinia. 

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376

Table 1 - Populations data and seed lot details. 

Accession Collection Collection Coordinates 

s Date site 

VIL 

CAG 08 

CAG 09 

MAS 

TEU 

24/10/200 

8 

Serra de 

Morus 

(Villasimius 

) 

07/08/200 

8 Tuvixeddu 

30/09/200 

9 

30/09/200 

9 

30/09/200 

9 

(Cagliari) 

Is Solinas 

(Masainas) 

Tuerredda 

(Teulada) 

39þ7'8.40"N 

9þ31'15.44"E 2 

39þ13'44.34" 

N 

9þ 6'11.59"E 

Altitud 

e 

(m) 

55 

39þ1'16.23"N 

8þ34'42.73"E 3 

38þ53'42.87" 

N 

8þ48'50.70"E 

2 

Substrate 

Lithology 

Coastal 

sands/ 

Granites 

Compacted 

clays/ 

Limestone 

s 

Coastal 


Granites 

Coastal 


Granites 

Thermotyp 

e 

Ombrotype 

Termomedit. 

Inf. 

Dry sup. 

Termomedit. 

Inf. 

Dry inf. 

Termomedit. 

Inf. 

Dry inf. 

Termomedit. 

Inf. 

Dry inf. 

Salt in 

substrat 

e 

NaCl 

from 

marine 

spray and 

sea layer 

Different 

salts 

NaCl 

from 

marine 


sea layer 

NaCl 

from 

marine 


sea layer 

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Invaded 

vegetation 

Pistacio 

lentisci- 

Juniperetum 

macrocarpa 

e 

Asparago 

albi-Oleetum 

sylvestris 

Pistacio 

lentisci- 

Juniperetum 

macrocarpa 

e 

Pistacio 

lentisci- 

Juniperetum 

macrocarpa 

e 

Habitat 

Directive 

92/43/EEC 

*Coastal 

dunes with 

Juniperus spp 

(2250) 

Thermo- 

Mediterranea 

n and predesert 

scrub 

(5330) 

*Coastal 

dunes with 

Juniperus spp 

(2250) 

*Coastal 

dunes with 

Juniperus spp 

(2250) 

Storage 

condition 

s 

1 year at 

15þC and 

15% R.H. 

1 year at 

15þC and 

15% R.H. 

Fresh 

seeds 

Fresh 

seeds 

Fresh 

seeds 

377

Germination protocols and salt tolerance 

According to international protocols (Bacchetta et al., 2006, 2008; ISTA, 2006), trials at 

different temperatures were performed. A pre-treatment was applied in order to overcome the 

physical dormancy, consisting in a mechanical scarification with sandpaper and then soaking in 

water. Based on previous works on germination of Acacia saligna, that indicated 20þC and 21þC 

as the best temperatures for this species (Liu et al., 2008), a range of temperatures from 15þC to 

30þC was selected for the trials. Four replicates of 10 seeds per treatment of each population were 

sown on the surface of 1% agar water in 90 mm plastic Petri dishes and incubated at 15þC, 20þC, 

25þC and 30þC with 12 hours light and 12 hours dark. Germination was scored daily for 90 days 

and germinated seeds were removed; they were considered to have germinated at the emergence 

of the radicle. The T50 parameter, time to reach 50% of the total germination, was also 

calculated. At the end of the germination tests, a cut test was carried out to determine the viability 

of the remaining seeds. The final germination percentage was calculated as the mean of the four 

replicates (± 1 standard deviation) on the basis of the total number of filled seeds. At the same 

conditions (15þC, 20þC, 25þC, 30þC with 12 hours light/12 hours dark), four replicates with 10 

seeds in each were sown with 1% and 2% NaCl concentrations in 1% agar water. Germination 

was scored daily, T50 parameter was calculated. 


Data were analyzed by Two-Way ANOVA to verify if there were any differences among 

populations and between fresh and dry seeds, and by One-Way ANOVA followed by the post 

hoc Fisher‘s LSD test to verify differences among temperatures and salinity treatments. The 

analyses were carried out using STATISTICA 7.0 software (Statsoft). 

Results 

Germination tests 

The optimal temperature range for germination of all populations of Acacia saligna was 15- 

20þC, but also at 25þC germination was very high (Table 2, Figure 2). The accessions showed a 

quite similar behavior, although with some differences: VIL and CAG 09 populations reached 

their best result at 15þC but they were also very high at 20þC; CAG 08 population, on the 

contrary, germinated better at 15þC and 25þC. MAS and TEU were the two accessions that had 

the most similar behavior between each other: the highest values were found at 20þC, followed 

by 25þC, 15þC and finally 30þC. In spite of this heterogeneity, all the values reached at 15þC, 

20þC and 25þC did not significantly differ one with the other (p > 0.05 by One-Way ANOVA 

followed by the post hoc Fisher‘s LSD test), with the exception of CAG 09 at 25þC. The only 

condition that seemed to represent a significant limit for A. saligna germination in all accessions 

was the temperature of 30þC (p < 0.01 by One-Way ANOVA followed by the post hoc Fisher‘s 

LSD test). Comparing the germination values for the accessions CAG 08 and CAG 09, 

originating from the same population (Table 1), they did not show significant differences at 15þC, 

20þC and 25þC (p > 0.05 by One-Way ANOVA followed by the post hoc Fisher‘s LSD test); but 

in both accessions the germination fell remarkably and significantly at 30þC. In particular, CAG 

09 reached a significantly lower final seed germination percentage not only with respect to CAG 

08 but also to the other seed lots (Table 2, Figure 2). On the whole, it may be said that the two 

seed lots do not show a relevant interannual variability and that the year of storage at the BG- 

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378

SAR had no influence on the viability and germination response of seeds of CAG 08 with respect 

to those of CAG 09. In fact, neither an interpopulation nor an interannual effect was detected on 

final seed germination percentages (p > 0.05 by Two-Way ANOVA). 

From the cut test carried out at the end of the trials, the total viability of the seeds (germinated 

plus viable) was of 100.00 ± 0.00. 

Figure 2 - Final germination at tested temperatures (15þC, 20þC, 25þC, 30þC) with a 

photoperiod of 12 hours light/12 hours dark for the seeds belonging to the five accessions of 

Acacia saligna. Data are the mean of four replicates (± standard deviation), p < 0.05 by One- 

Way ANOVA followed by the post hoc Fisher‘s LSD test. 

Salt tolerance 

Salt concentration increase influenced the germinative capacity (Table 2, Figure 3), causing a 

decrease in final percentages. 

At 1% of NaCl concentration the germination fell remarkably; the final values stayed rather high 

only at 15þC, being almost always above 60% with the exception of CAG 08. At 20þC, with the 

exception of CAG 09 and TEU, it went under 50%. Of these latter cases, only the germination 

percentage of CAG 09 turned out to be statistically similar to the values reached at 15þC by VIL, 

CAG 09, MAS and TEU (p > 0.05 by One-Way ANOVA followed by the post hoc Fisher‘s LSD 

test) (Table 2, Figure 3). At 25þC only VIL, MAS and TEU germinated but reached very low 

values, significantly different both with respect to those at 15þC and to those at 20þC (with the 

exception of VIL at 20þC). Finally, at 30þC none of the accessions were able to germinate. 

At 2% of NaCl concentration, final germination percentages stayed relatively low and it occurred 

almost only at 15þC (Table 2, Figure 4). The accession that germinated better was CAG 08 

followed by VIL, CAG 09 and MAS, being the latter two statistically different (p < 0.05 by One- 

Way ANOVA followed by the post hoc Fisher‘s LSD test). At 20þC only CAG 08 could 

germinate, this value being significantly different from VIL, CAG 08, CAG 09 and MAS at 15þC 

(p < 0.05 by One-Way ANOVA followed by the post hoc Fisher‘s LSD test). Conversely, at 

25þC and 30þC none of the accessions germinated. Again, there were no statistical differences in 

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379

the final seed germination percentages neither among populations nor between storage conditions 

(p > 0.05 by Two-Way ANOVA). 

Figure 3 - Final germination at tested temperatures (15þC, 20þC, 25þC, 30þC) with a 


Acacia saligna with 1% NaCl in the medium. Data are the mean of four replicates (± standard 

deviation), p < 0.05 by One-Way ANOVA followed by the post hoc Fisher‘s LSD test. 

Figure 4 - Final germination at the tested temperatures (15þC, 20þC, 25þC, 30þC) with a 


Acacia saligna with 2% NaCl in the medium. Data are the mean of four replicates (± standard 

deviation), p < 0.05 by One-Way ANOVA followed by the post hoc Fisher‘s LSD test. 

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380

NaCl concentration in the medium caused not only a decrease in the final germination 

percentages but also a delay of this latter. In fact comparing the T50 values (Table 2) for the trials 

at 15þC (the only temperature that allowed germination at both NaCl concentrations), it is 

important to notice that they augmented with the enhancement of salinity (see Table 2). 

Table 2 - Final germination percentages (± standard deviation) and T50 values (in italics) of 

Acacia saligna at 15þC, 20þC, 25þC, 30þC in the control test (0% NaCl), with 1% and 2% 

NaCl in the medium. Data are the means of four replicates. 

Accession Control test, 0% NaCl 

1% NaCl 2% NaCl 

VIL 

CAG 08 

CAG 09 

MAS 

TEU 

Discussion 

15°C 

100.00 

± 0.00 

0.83 

92.50 

± 9.57 

1.93 

95.00 

± 

10.00 

2.27 

82.50 

± 5.00 

2.16 

82.50 

± 5.00 

2.23 

20°C 

95.00 ± 

10.00 

0.73 

82.50 ± 

9.57 

1.55 

90.00 ± 

11.55 

0.64 

90.00 ± 

8.16 

0.67 

87.50 ± 

12.91 

0.77 

25°C 

75.00 ± 

30.00 

7.71 

95.00± 

5.77 

3.56 

80.00 ± 

8.16 

0.73 

85.00 ± 

12.91 

2.00 

82.50 ± 

23.36 

4.33 

30°C 15°C 20°C 25°C 30°C 15°C 20°C 25°C 30°C 

60.00 ± 

18.26 

11.00 

52.50 ± 

15.00 

17.42 

12.50 ± 

18.93 

0.83 

80.00 ± 

8.16 

9.82 

47.50 ± 

9.57 

14.50 

75.00 

± 

10.00 

7.80 

50.00 

± 

14.14 

10.17 

82.50 

± 

5.00 

7.10 

75.00 

± 

20.82 

8.00 

62.50 

± 

17.08 

5.50 

12.50 

± 

12.58 

8.50 

40.00 

± 

14.14 

17.80 

72.50 

± 

5.00 

13.20 

42.50 

± 

17.08 

11.63 

52.50 

± 

15.00 

7.29 

7.50 

± 

9.57 

8.50 

0.00 

± 

0.00 

0.00 

± 

0.00 

2.50 

± 

5.00 

3.00 

7.50 

± 

8.16 

18.50 

0.00 

± 

0.00 

0.00 

± 

0.00 

0.00 

± 

0.00 

0.00 

± 

0.00 

0.00 

± 

0.00 

30.00 

± 

8.16 

18.00 

40.00 

± 

29.44 

35.89 

5.00 

± 

5.77 

21.50 

2.50 

± 

5.00 

25.50 

20.00 

± 

23.09 

24.25 

0.00 

± 

0.00 

7.50 

±9.57 

22.00 

According to the germination tests‘ results, seeds belonging to the Sardinian populations of 

Acacia saligna show the capacity to germinate to a great extent at all tested temperatures. This 

result can be interpreted as a sign of the capacity of this species to rapidly adapt to environmental 

changes. The result of the cut test carried out at the end of the germination trials, with all seeds 

full and viable, confirms the effectiveness of the dispersal mechanism of this species that can set 

up a persistent seed bank (PSB). This result is also coherent with previous studies carried out by 

Milton & Hall (1981) and Richardson & Kluge (2008). 

The strong interaction between salt and temperature must be pointed out: it is clear that with 

salt presence, the germination capacity of A. saligna seeds is higher at low temperatures and it 

0.00 

± 

0.00 

0.00 

± 

0.00 

0.00 

± 

0.00 

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0.00 

± 

0.00 

0.00 

± 

0.00 

0.00 

± 

0.00 

0.00 

± 

0.00 

0.00 

± 

0.00 

0.00 

± 

0.00 

0.00 

± 

0.00 

0.00 

± 

0.00 

0.00 

± 

0.00 

0.00 

± 

0.00 

381

progressively decreases as the temperature increases. This fact is ecologically significant, 

indicating a need for a reduction in soil salinity for seed germination to occur. In fact, seed 

germination in saline environments usually occurs in spring when the temperatures are lower and 

soil salinity is reduced by precipitation in the late winter and spring (Katembe et al., 1998; Ungar, 

1995; Zehra & Kahn, 2007). The above mentioned behavior is common to the seeds of most of 

species, including halophytes, that show optimal germination in fresh water (Boorman, 1968; 

Khan & Ungar, 1984; Macke & Ungar, 1971; Waisel & Ovadia, 1972) while increased salinity 

leads to a reduction in germination of both halophyte and glycophyte seeds (Ungar, 1995; Waisel 

& Ovadia, 1972). Sometimes, as in the case of A. saligna, salt may affect germination rate to an 

equal or greater extent than germination final percentage (Lovato et al., 1994). Furthermore the 

germination of halophytes shows a characteristic pattern in response to increased salt levels, with 

higher resistance up to a certain critical concentration and then a rapid decrease in final 

germination beyond this (Meloni et al., 2008); glycophytes, on the other hand, show a 

concomitant reduction in germination with increasing salinity (Rogers et al., 1995). 

The present germination data therefore suggest that A. saligna is a salt-tolerant glycophyte, 

that it is able to live in many different substrata and in a wide range of habitats, while halophytes 

are generally restricted to saline environments, thus indicating either a requirement for relatively 

high salt concentrations, a tolerance for excess salts, or a decreased competitive ability with other 

plants in less stressful environments (Katembe et al., 1998; Ungar, 1995). The hypothesis is also 

supported by the first results of the in situ monitoring in the SIC area ―Isola dei Cavoli, 

Serpentara e Punta Molentis‖ in the administrative territory of Villasimius (SE Sardinia) (Podda 

et al., 2009). During the monitoring study the invasiveness and expansion of the species has been 

detected and recognized as a threat to the prioritary habitat ―2250 Coastal dunes with Juniperus 

spp‖ of the Habitat Directive 92/43/EEC (European Community, 1992). In fact, 

phytosociological relevés highlighted the dominance of A. saligna over Juniperus oxycedrus L. 

subsp. macrocarpa (Sibth. & Sm.) Neilr., with cover indexes that reached up to 100%. 

Nevertheless, preliminary data show that A. saligna shrub formations principally evolve towards 

fixed dunes. The expansion of the species towards the coastline is limited by the presence of the 

salt marine spray that probably represents the main limiting factor together with the wind speed 

and sand transport rates. Rather, the colonization of the species towards the inland sector seems 

not be limited by any factor. In fact, A. saligna appears to be strongly favored in the perturbed 

sector, where the formations with J. oxycedrus subsp. macrocarpa are affected by continuous 

cuts and openings that consequently degrade the habitat and enhance the penetration of alien 

woody species. 

Considering the threat posed by this species for coastal habitats, especially for the prioritary 

European habitat ―2250 Coastal dunes with Juniperus spp‖, it is important to take into account 

the management measures which are necessary to limit the invasion of this species, incorporating 

them in the territory planning. Due to the danger of dramatically altering the dunes ecosystem 

structure, A. saligna is really difficult to control through mechanical methods such as the removal 

of adult individuals. Richardson & Kluge (2008) suggest the use of controlled fires in order to 

limit the soil seed bank, which is an inappropriate method to apply in important and fragile 

ecosystems such as coastland dunes. The interaction between temperature and salt concentration 

in the germination stage of A. saligna allows identifying spring as the season when most 

germination takes place in coastal habitats with presence of NaCl. We therefore suggest that the 

manual eradication of the seedlings in the appropriate season, together with the cut of adult 

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382

individuals, is probably the only method that could give a contribution to the effective control of 

this species, preventing further development of individuals before they turn into threats and, at 

the same time, reducing any disturbance to autochthonous species and plant communities. 

With regard to climate change, the global increase of temperatures is projected to enhance the 

expansion of alien species coming from hot areas, and to facilitate opportunist and fast-growing 

taxa (Kriticos et al., 2003; Middleton, 2006). Our investigations demonstrate that the germination 

capacity of A. saligna decreases with the increase of temperatures, this behavior being 

emphasized by the presence of salt in the germination substrate. For this reason it is presumable 

that the projected increase in temperatures and in summer drought length could limit the 

distribution of this species to more reduced areas. On the other hand, according to the results of 

germination tests, A. saligna shows a tolerance to NaCl at the germination stage, and a certain 

amount of interpopulation variability that can be interpreted as a sign of the capacity of this 

species to rapidly adapt to environmental changes. These factors will likely lead, either in 

Sardinia as well as in other Mediterranean territories, to an expansion of the populations of this 

species. 

The present work contributes to the knowledge of the seed ecology and germination behavior 

of the invasive A. saligna in the Mediterranean basin, by bringing new data on the response of the 

species to different temperatures regimes and salinity concentration. The article also provides 

new data about the interpopulation and interannual variability. 


This study has partially been supported by the Doctoral School of ―Ingegneria e Scienze per 

l‘Ambiente e il Territorio‖ of the Università degli Studi di Cagliari and has received a RAS 

research grant cofinanced by PO Sardegna FSE 2007-2013 L.R.7/2007 ―Promozione della ricerca 

scientifica e dell‘innovazione tecnologica in Sardegna‖. Authors want to thank Emanuela 

Bacchetta for English revision. 

References 

Aref IM (2000) Effects of pre-germination treatments and sowing depths upon germination potential of some Acacia 

species. Research Bulletin of King Saudi University 95, 5-17. 

Aru A (1967) [Observations on ―Is Arenas‖ soils (Oristano).] Typography R. Coppini & C. (in Italian). 

Bacchetta G (2006) [The flora of Sulcis (South-Western Sardinia).] Guineana 12, 1-369 (in Italian). 

Bacchetta G, Fenu G, Mattana E, Piotto B & Virevaire M (eds) (2006) Manuale per la raccolta, studio, 

conservazione e gestione ex situ del germoplasma. Manuali e Linee guida APAT 37/2006 (IT). 

Bacchetta G, Bueno Sánchez A, Fenu G, Jiménez-Alfaro B, Mattana E, Piotto B & Virevaire M (eds) (2008) 

Conservación ex situ de plantas silvestres. Principado de Asturias, La Caixa (SP). 

Bacchetta G, Mayoral Garcìa-Berlanga O & Podda L (2009) [Checklist of the exotic flora of Sardinia (Italy).] Flora 

Montiberica 41(1), 35-61 (in Spanish). 

Baskin CC & Baskin JM (1998) Seeds–ecology, biogeography and evolution of dormancy and germination. 

Academic Press, San Diego, CA (US) 

Baskin JM & Baskin CC (2004) A classification system for seed dormancy. Seed Science Research 14, 1-16. 

Bocchieri E & Iiriti G (2003) [Flora of Teccu, a basaltic promontory of the Central-Eastern Sardinia.] Atti della 

Società Toscana di Scienze Naturali, Serie B, 110, 35-53 (in Italian). 

Boorman LA (1968) Some aspects of the reproductive biology of Limonium vulgare Mill. and Limonium humile 

Mill. Annals of Botany 32, 803-824. 

Posters 


383

Brundu G, Camarda I, Hulme PE, Vilà M, Troumbis A, Traveset A, Moragues E & Suehs C (2004) Comparative 

analysis of the abundance and distribution of alien plants on Mediterranean islands. Proceedings of 10th 

MEDECOS, International Conference on Ecology Conservation and Management of Mediterranean Climate 

Ecosystems. Rhodes (GR). 

Camarda I, Brundu G, Carta L, Manca M, Satta V (2002) Invasive alien plants in the National Parks of Sardinia. In 

Global challenges of parks and protected area management (eds Camarda I, Manfredo MJ, Mulas F & Teel 

T). Proceedings of the 9 th ISSRM. Carlo Delfino Ed., Sassari (IT). 

Celesti-Grapow L, Alessandrini A, Arrigoni PV, Banfi E, Bernardo L, Bovio M, Brundu G, Cagiotti MR, Camarda I, 

Carli E, Conti F, Fascetti S, Galasso G, Gubellini L, La Valva V, Lucchese F, Marchiori S, Mazzola P, 

Peccenini S, Pretto F, Poldini L, Prosser F, Siniscalco C, Villani Mc, Viegi L, Wilhalm T & Blasi C (2009) 

The inventory of the non-native flora of Italy. Plant Biosystems 143(3), 386-430. 

Cronk QCB & Fuller J (1995) Plant Invaders. Chapman & Hall, London (UK). 

Conti F, Abbate G, Alessandrini A & Blasi C (eds) (2005) An Annotated Checklist of the Italian Vascular Flora. 

Palombi Editori, Roma (IT). 

Doran J & Turnbull J (1997) Australian trees and shrubs: species for land rehabilitation and farm planting in the 

tropics. ACIAR, Canberra (AUS). 

European Community, 1992. Council Directive 92/43/EEC of 21.5.92. Official Journal of the European Community. 

L. 206 of 22/7/1992. 

Fenu G & Bacchetta G (2008) [The vascular flora of the Sinis peninsula (Western Sardinia).] Acta Botanica 

Malacitana 33, 91-124 (in Italian). 

Groves RH (ed) (1994) Australian vegetation. Cambridge University Press, Cambridge (UK). 

Guarino L, Ramanantha Rao V & Reid R (eds) (1995) Collecting Plant Genetic Diversity. Technical guidelines. 

CABI. Wallingford, Oxon (UK). 

Henderson L (2001) Alien weeds and invasive plants. Plant Protection Research Institute Handbook No. 12. 

Agricultural Research Council, Pretoria (ZA). 

Holmes PM, Richardson DM, Esler KJ, Witkowski ETF & Fourie S (2005) A decision-making framework for 

restoring riparian zones degraded by invasive alien plants in South Africa. South African Journal of Science 

101, 553-564. 

ISTA (2006) International rules for seed testing. Edition 2006. The International Seed Testing Association (ISTA), 

Bassersdorf (CH). 

Katembe WJ, Ungar IA & Mitchell JP (1998) Effect of salinity on germination and seedling growth of two Atriplex 

species (Chenopodiaceae). Annals of Botany 82, 167-175. 

Khan MA & Ungar IA (1984) The effect of salinity and temperature on germination of polymorphic seeds and 

growth of Atriplex triangularis. American Journal of Botany 71, 481-489. 

Kriticos D, Sutherst R, Brown J, Adkins S & Maywald G (2003) Climate change and the potential distribution of an 

invasive alien plant: Acacia nilotica ssp. indica in Australia. Journal of Applied Ecology 40, 111-124. 

Liu K, Eastwood RJ, Flynn S, Turner RM & Stuppy WH (2008) Seed Information Database 

http://www.kew.org/data/sid [release 7.1, May 2008]. 

Lovato MB, Martins PS & Lemos JPD (1994) Germination in Stylosanthes humilis populations in the presence of 

NaCl. Australian Journal of Botany 42(6), 717-723. 

Lubke RA (1985) Erosion of the beach at St Francis Bay, Eastern Cape, South Africa. Biology Conservation 32, 99- 

127. 

Macke AJ & Ungar IA (1971) The effect of salinity on germination and early growth of Puccinella nuttalliana. 

Canadian Journal of Botany 49, 515-520. 

Mayer A (1995) Comparative study of the coastal vegetation of Sardinia (Italy) and Crete (Greece) with respect to 

the effects of human influence. Libri Botanici 15. 

Meloni DA, Gulotta MR & Martìnez CA (2008) Salinity tolerance in Schinopsis quebracho colorado: seed 

germination, growth, ion relations and metabolic responses. Journal of Arid Environments 72(10), 1785-1792. 

Middleton B (2006) Invasive species and climate change open-file report 2006-1153. U.S. Department of the 

Interior, U.S. Geological Survey (US). 

Milton SJ & Hall AV (1981) Reproductive biology of Australian acacias in the southwestern Cape Province, South 

Africa. Transactions of the Royal Society of South Africa 44, 465-487. 

National Academy of Sciences (N.A.S.) (1980) Firewood crops. Shrub and tree species for energy production. US 

National Academy of Sciences, Washington DC (US). 

Piotto B & Di Noi A (eds) (2003) Seed propagation of Mediterranean trees and shrubs. National Agency for the 

Environmental Protection (ANPA). Roma (IT). 

Posters 


384

Podda L, Meloni F, Dettori CA, Mascia F, Soriano García JA & Bacchetta G (2009) Weed risk assessment of Acacia 

saligna in Sardinian coastland habitats through ex situ germination study and in situ monitoring. Book of 

Abstract 45° International Congress SISV & FIP. Cagliari (IT). 

Podda L, Fraga i Arguimbau P, Mayoral Garcìa-Berlanga O, Mascia F & Bacchetta G (2010) [Comparison of the 

vascular exotic flora in continental islands: Sardinia (Italy) and Balearic Islands (Spain).] Anales Jardin 

Botanico de Madrid 67(2), 157-176 (in Spanish). 

Richardson DM, MacDonald IAW & Forsyth GG (1989) Reductions in plant species richness under stands of alien 

trees and shrubs in the fynbos biome. South African Forestry Journal 149, 1-8. 

Richardson DM, Pyšek P, Rejmánek M, Barbour MG, Panetta FD & West CJ (2000) Naturalization and invasion of 

alien plants: concepts and definitions. Diversity and Distributions 6, 93-107. 

Richardson DM & Kluge RL (2008) Seed banks of invasive Australian Acacia species in South Africa: role in 

invasiveness and options for management. Perspectives in Plant Ecology, Evolution and Systematics 10, 161- 

177. 

Rogers ME, Noble CL, Halloran GM & Nicolas ME (1995) The effect of NaCl on germination and early seedling 

growth of white clover (Trifolium repens L.) populations selected for high and low salinity tolerance. Seed 

Science Technology 23, 277-287. 

Simmons MH (1987) Study the growing acacias establishment of planted tree seedlings. Marcel Kenthurst Kangaroo 

Press, Publishing (AU). 

Ungar IA (1995) Seed germination and seed-bank ecology in halophytes. In Seed development and germination (eds 

Kigel J & Galili G), pp. 599-628. Marcel Dekker, New York (US). 

Van Wilgen BW & Richardson DM (1985) The effects of alien shrub invasions on vegetation structure and fire 

behaviour in South African fynbos shrublands: a simulation study. Journal of Applied Ecology 22, 955-966. 

Vilà M, Valladares F, Traveset A, Santamarìa L & Castro P (eds) (2008) Invasiones biológicas. CSIC, Madrid (SP). 

Waisel Y & Ovadia S (1972) Biological flora of Israel. Suaeda monica Forsk. ex J.F. Gmel. Israel Journal of Botany 

21, 42-52. 

Zehra A & Khan MA (2007) Comparative effect of NaCl and sea salt on germination of halophytic grass Phragmites 

karka at different temperature regimes. Pakistan Journal of Botany 39(5), 1681-1694. 

Posters 


385

Assessing the potential invasiveness of Cortaderia selloana in Sardinian wetlands through 

seed germination study. 

Lina Podda, Italy 

Centro Conservazione Biodiversità (CCB), Dipartimento di Scienze Botaniche, Università degli 

Studi di Cagliari., Italia 

E-mail: linap68@yahoo.it 

The present work focuses on the study of abiotic factors that may favour seed germination and 

the potential invasiveness of C. selloana, with particular attention to wetlands. Germination tests 

were conducted at the Sardinian Germplasm Bank (BG-SAR), testing different temperatures and 

percentages of NaCl in order to determine the optimal ecological conditions at which germination 

occurs and the effect of salt on seeds germination and viability, as well as on seedling 

development. Seeds completely germinated at every tested temperature, yet the higher 

germination rate was found at 25þC. Salinity did not prevent seeds from germinating, but it 

affected germination rate and seedling vigour. The population that has been taken into account in 

this study is located in a continental and non-artificial wetland context, whose vegetation is 

represented by hygrofile formations with Phragmites australis (Cav.) Trin. ex Steud and by 

Carex sp.pl. in the banks, belonging to Phragmito-Magnocaricetea Klika in Klika et Novàk 

1941, followed by communities of the order Juncetalia maritimi Br.-Bl. ex Horvatic 1934 in the 

depressed areas and by therophytic formations of the class Isoëto-Nanojuncetea in temporary 

wetlands. The results of the germination tests that have been carried out prove the potential 

invasiveness of C. selloana in habitats such as lagoons and salt marshes. 

Posters 


386

Industry view on importance and advantages of a Code of Conduct on horticulture and 

invasive alien plants 

Anil Yilmaz 

Antalya Exporter Unions General Secretariat, Turkey 

E-mail: yilmaza@aib.org.tr 

The International Association of Horticultural Producers (AIPH) represents horticultural 

producers' organisations all over the world. The horticultural industry supports the aim to 

preserve the biological diversity. The reinforcement of the biological diversity in urban areas, the 

improvement of the greening in cities is considered and supported as the essential aim of national 

strategies for biological diversity. Therefore AIPH has interest in the prevention of introduction 

and spread of invasive plants. Their interest is that a Code of Conduct is set up by the sector itself 

or in partnership with government and/or NGO‘s. A code may not just be layed upon the sector 

by the authorities. The rules have to be made by and in agreement with the target group. They 

also can agree on the sanctions, within ethical and legal boundaries. 

Introducing a Code of Conduct can only be successful if there is awareness of the problem and 

stakeholders find it their responsibility to take preventive measures. The organisation that edits 

the Code of Conduct has to be representative for the sector. The form and the content have to be 

accessible, consistent, applicable, realistic and feasible. 

To be effective a Code needs incentives, compliance and assurance. Major reasons to encourage 

self-regulations are 1) preventing government regulation, 2) concern for the image of the sector, 

3) concern for the environment and 4) corporate social responsibility. Although Code of 

Conducts is not a new way of self-regulation, in the horticultural sector it is relatively new. Since 

the middle of the 90-ties codes of conduct or code of practice have been introduced in the field of 

environment and social aspects. Some Codes of Conduct or Code of Practice for preventing the 

spread of invasive plants have been introduced in the last few years. Other initiatives like Action 

Plans or Management Plans towards invasive species, edit by governments, are more compulsory. 

Posters 


387

Anigozanthos hybrids: what are the chances of eradicating this flower-farm escapee? 

Ivey Philip 

Early Detection Programme, SANBI, Private Bag X7, Claremont, 7735, South Africa 

E-mail: p.ivey@sanbi.org.za 

Anigozanthos species (Kangaroo paws) endemic to Western Australia were introduced as a 

possible cut flower to a farm outside Kleinmond, in the Western Cape, South Africa. The species 

is well adapted to the climatic conditions and fire regimes of the Cape floristic region and has the 

potential to spread and threaten wetland habitats in the adjacent Kogelberg Biosphere reserve. 

While the threat to water resources and environmental services is likely to be low, the threat to 

indigenous and possibly endangered wetland species being displaced by monocultures of 

Anigozanthos is high. After initial assessments and surveys that delimited the known distribution 

of the hybrids to six populations, long term monitoring sites have been set up and physical 

clearing of the species has begun. Based on initial understanding of the population dynamics 

developed from data gathered during clearing operations, this paper will explore the likelihood of 

eradication of the species. The Nursery Industry has yet to be convinced of the invasive potential 

of this genus and its hybrids and claim the right to import ‗sterile‘ hybrids of Anigozanthos. The 

complexities of dealing with a stakeholder that has an economic interest in a potentially invasive 

species will also be explored. 

Posters 


388

Use of “native species” as a bioenergy crop in the Mediterranean basin. Concerns regarding 

invasive traits of some domesticated taxa: the case of Cardoon (Cynara cardunculus) 

Roberto Crosti Roberto 1 and Leak-Garcia Janet A 2 

1 

c/o ISPRA Dipartimento Difesa della Natura -Tutela biodiversità, Roma, Italy. E-mail: 

roberto.crosti@isprambiente.it 

2 

Department of Botany and Plant Sciences, University of California, Riverside, USA 

Biofuel crops have many traits in common with the ideotype of an invasive 

species, thus several reports and agroenergy feasibility plan suggest using 

native species (sensu latu), rather than alien, as biofuel crop to avoid that 

invasive alien germplasm could lead to habitat loss and biodiversity harm. It 

should be noted, however, that even native species that are dominant within 

particular habitats are not efficient in phytomass production. So to be harvested 

for biofuel production, most of the species ―claimed‖ as native in cropping 

systems are, in fact, species with a ―wild relative/genotype‖, selected or 

domesticated for specific traits which may confer, among the others, greater 

invasiveness capacity. 

In different countries of the Mediterranean Basin, the ―native‖ cardoon (Cynara 

cardunculus var. altilis –DC) has been an object of research in order to study 

the biological and agronomic responses of different cultivars for biofuel 

production. Cardoon, as a consequence of being domesticated from the ―genetic 

pool‖ of the native wild artichoke Cynara cardunculus var. sylvestris is adapted 

to mediterranean environments. Spread of germplasm of the ―wild related‖ 

species into natural habitat may impact native biological diversity as it can 

compete with native vegetation and increase hybridization (impacting the 

genetic integrity) with congeneric native species. New hybrids, in addition, can 

compete better for resources with the other species of the native plant 

community. 

Since the initial alert of the scientific community (Crosti & Forconi 2006; Raghu et al. 2006) 

and of relevant conservation organization or international bodies (GISP 2008; IUCN 2009, CoE 

2009) concerning the potential risk of several biofuel species, which many countries are 

promoting as an alternative to fossil fuels, to ―escape the field‖ and become invasive and harm 

the natural environment, many feasibility plan of biofuel crops suggest the use of native species. 

In agro-ecosystems, in fact, anthropogenic manipulation of land for agricultural production 

has greatly changed the original natural ecosystem and the agriculture practices facilitate the 

spread of invasive alien plants, making the natural environment more susceptible to invasions. 

Indeed, farmlands are habitats prone to new introductions, plant naturalisation and invasion. 

Worldwide and in Europe, most invasive alien species were introduced for agricultural and 

horticultural purposes and biofuel crops have many traits in common with the ideotype of an 

invasive species including broad ecological amplitude, rapid growth, high seed production, 

common occurrence of vegetative spread, and resistance to pests and diseases. 

Posters 


389

The use of native species (sensu latu), rather than alien, as biofuel crop to reduce habitat loss 

and biodiversity harm, subsequent to alien plant invasiveness, is thus commonly suggested. It 

should be noted, however, that even native species that are dominant within particular habitats 

(i.e. in grasslands or in high stand forests) are not efficient in industrial phytomass production. So 

to be harvested for biofuel production, most of the species ―claimed‖ as native in cropping 

systems are, in fact, species with a wild relative, selected or domesticated for specific traits which 

may confer, among the others, greater invasiveness capacity. 

In different countries of the Mediterranean Basin, the ―native‖ cardoon (Cynara cardunculus 

var. altilis –DC) has been an object of research in order to study the biological and agronomic 

responses of different cultivars. Subsequently it has been proposed for use as a drought resistant 

biofuel crop capable of producing high yields especially in dry summer climate conditions. The 

species can be used for biomass from the stalk, sugar from the roots and oil from seeds. Cardoon 

plants used for the biofuel industry are harvested dry from the end of the summer, thus 

eliminating the great cost of moisture contents in crops that affect harvesting, transportation and 

storage. 

Cardoon, as a consequence of being domesticated from the ―genetic pool‖ of a native species 

(Rottemberg et al., 2005), is adapted to mediterranean environments. Cardoon grows mainly 

from seed and was domesticated from the wild artichoke, Cynara cardunculus var. sylvestris 

which is a perennial species which remains completely interfertile with cardoon (Sonnante et al., 

2007) and with many local genotypes; in Sicily i.e. Raccuia et al. (2004) found out, using genetic 

markers, that eco-geographical groups within wild cardoon are clearly separated, and reflect the 

geography of the different collection areas. 

According to Wiklund (1992) the species‘ var. sylvestris can be divided into two different 

taxa: ssp. cardunculus (occurring in Italy and on the eastern side of the Mediterranean basin) and 

ssp. flavescens (occurring in Sicily, in Spain and as a weed in other med-type climates regions). 

The physiological and reproductive traits of cardoon make it a potentially invasive species. When 

Cynara cardunculus var. altilis potential invasivity was estimated through an adaptation of the 

Australian Weed Risk Assessment (Crosti et al., 2010), the final score, which could have been 

underestimated due to absence of agronomic information of new cultivars, was high (16) and the 

final outcome assessed that the species should be rejected from being cultivated. The assessment 

gives a low score for domesticated species, but by contrast it is not the case for the cardoon, 

reduces weediness. 

Consequently the germplasm escaped from cardoon plantation could harm different types of 

habitats such as: the Mediterranean, arid and semi-arid, grassland habitats of native thistle plant 

communities (Onopordetea acanthi- Artemisienea vulgaris; [Ordo]-Carthametalia lanati); the 

Natura 2000 habitats of pseudo-steppe with grasses and annuals (Thero-Brachypodietea); the old 

fields (Brometalia rubenti-tectorum) where they could slow down the secondary succession 

vegetation dynamic of the re-naturalization processes. In addition, within agroecosystems, 

grazing increases the species presence due to its inedibility. Cardoon was initially domesticated 

for its stalk size and then selected for biofuel cultivations, especially from Spanish genotypes. 

Cardoon as a biofuel crop is distinguished by its rapid growth, efficient use of water resources 

and great reproduction capacity (Pignatelli et al., 2006). Surveys undertaken in Southern Italy‘s 

mediterranean habitats within experimental farmland fields showed that cardoon ―crop escape‖ 

Posters 


390

was already underway (Crosti et al., 2008). Consequently, the taxon poses a double threat: it may 

lead to hybridization with different populations of wild artichokes, and it may compete for natural 

resources with other native species especially in disturbed habitats. Species selected traits, 

together with the cropping system (annual planting, large scale intensive cultivations in different 

areas, harvest dry at senescence when pollination and seed dispersion are likely to have already 

occurred) make it a potentially invasive species even though domestication generally leads to 

reduced fertility. Cardoon is already considered a pest in other Mediterranean-type climate 

regions such as California, Western Australia and S. Africa (Marushia et al., 2008). In particular 

the Spanish genotype seems to be much more aggressive than the Italian one and in California it 

appears to have evolved into larger and more fecund individuals since their introduction (Holt & 

Garcia, 2009). For these reasons, when the species is selected and cultivated as a biofuel crop, 

specific cultivation criteria are needed to limit the weedy behaviour (i.e. use of non aggressive 

cultivars, cutting of flower heads to prevent breeding, harvesting before seed dispersal, and 

establishment of a buffer zone). Spread of ―wild relative‖ species into natural habitats may 

impact native biological diversity as it can compete with native vegetation and increase 

hybridization with congeneric native species (impacting genetic integrity). New hybrids, in 

addition, are better competitors for resource and space than are species of the native plant 

community. 

References 

Crosti R, Bianco P, Cardillo A & Piscioneri I (2008) Cynara weedness alert: quando coltivazioni intensive di un 

―wild related‖ possono arrecare danno alla biodiversità delle specie spontanee. Cantieri della biodiversità: La 

sfida delle invasioni biologiche, come rispondere? Siena 11-12 2008 

Crosti R, Cascone C & Cipollaro (2010) Use of a weed risk assessment for the Mediterranean region of Central Italy 

to prevent loss of functionality and biodiversity in agro-ecosystems. Biological Invasion 12, 1607-1616. 

Crosti R & Forconi V (2006) Espansione delle colture da biomassa sul territorio italiano: incognite legate 

all‘introduzione di specie aliene potenzialmente invasive. In Colture a scopo energetico ed ambiente. Atti 

Convegno APAT 2006. 

GISP (2008) Biofuel Crops and the Use of Non-native Species: Mitigating the Risks of Invasion. GISP, Nairobi, 

Kenya. 

Holt J & Garcia Jl (2009) Relationship of artichokes and cardoon to invasive artichoke thistle:should they be 

discouraged in the home garden? 

IUCN (2009) Guidelines on Biofuels and Invasive Species. IUCN, Gland, Switzerland. 

Marushia RG & Holt JS (2008) Reproductive strategy of an invasive thistle: effects of adults on seedling survival. 

Biological Invasions 10, 913-924. 

Pignatelli V, Piscioneri I, Sharma N (2006) Prospettive di sviluppo delle colture da biomassa negli ambienti 

dell‘Italia meridionale. In Colture a scopo energetico ed ambiente. Atti Convegno APAT 2006. 

Raccuia SA, Mainolfi A, Mandolino G & Melilli MG (2004) Genetic diversity in Cynara. Cardunculus L. revealed 

by AFLP markers: wild and cultivated taxa comparisons. Plant Breeding 123, 280-284. 

Raghu S, Anderson RC, Daehler CC, Davis AS, Wiedenmann RN, Simberloff D & Mack RN (2006) Adding 

biofuels to the invasive species fire? Science 313, 1742. 

Rottemberg A & Zohary D (2005) Wild genetic resources of cultivated artichoke. Acta Horticulturae 681, 307-311. 

Sonnante G, Pignone D & Hammer K (2007) The domestication of artichoke and cardoon: from Roman times to the 

genomic age. Annals of Botany 100, 1095-1100. 

Wiklund A (1992) The genus Cynara L. (Asteraceae: Cardueae). Bot. J. Linn. Soc. 109, 113 

Posters 


391

Control experiments on selected invasive alien species in the Bulgarian flora 

Vladimir Vladimirov 1 & Senka Milanova 2 

1 Institute of Botany, Bulgarian Academy of Sciences, Acad. Georgi Bonchev St., bl. 23, 1113 

Sofia, Bulgaria. E-mail: vdvlad@bio.bas.bg (Presenting author) 

2 Plant Protection Institute, Kostinbrod, Bulgaria 

Ailanthus altissima, Ambrosia artemisiifolia, Amorpha fruticosa, Fallopia × bohemica and Iva 

xanthiifolia are among the worst invasive alien species in the Bulgarian flora. During the past few 

decades they expanded their distribution ranges in the country and threatened to native 

biodiversity and/or human health. Therefore, experiments for control of these species have been 

designed and carried out within the project ‗Biology, ecology and control of the invasive alien 

species in the Bulgarian flora‘ (2009-2011). Ambrosia artemisiifolia and Iva xanthiifolia have 

been subjected to competition with selected forage plants such as Medicago sativa, Lolium 

perenne, Dacylis glomerata and Elymus repens. The latter species, especially L. perenne, D. 

glomerata and M. sativa, proved to be a reliable means to suppress the growth and seed 

production of the invasive species. Ailanthus altissima, Amorpha fruticosa and Fallopia × 

bohemica have been subjected to various combinations of mechanical (cutting, eradication, 

coverage) and chemical control (gliphosate treatment) measures. The three species, and 

especially F. × bohemica, showed high resistance to lower concentrations of glyphosate. The 

poster presents the experimental design and the results after the first year of the implementation 

of the control measures. 

Financial support of the Bulgarian National Science Fund under the project DO-02-194 is 

gratefully acknowledged. 

Posters 


392

Management of Ludwigia peploides (water primrose) in the Vistre River (South-East of 

France): first results 

Alain Dutartre 1 , C. Pezeril 2 , Emilie Mazaubert 1 

1 Cemagref, REBX, 50, Avenue de Verdun, 33612 Cestas Cedex, France 

E-mail : Emilie.mazaubert@cemagref.fr (Presenting author) 

2 SMBVV, 7 avenue de la Dame, 30132 Caissargues, France 

The water primrose, Ludwigia peploides, is an alien invasive aquatic species in the Mediterranean 

part of the South-East of France. It can invade many types of static or slow-flowing waters: 

rivers, shallow ponds and lakes, wetlands, etc. The biomass abundance and monospecific stands 

lead to local loss of floral and faunal biodiversity. 

L. peploides invaded many biotopes in the Vistre River, a 46 km long river highly affected by 

strong hydraulic modifications, close to the urban area of Nîmes (Gard). The impact of this 

species on native hydrophytes (for example Myriophyllum spicatum) is significant in some sites. 

A new watershed management plan was built in 2001 by the managers of the "Syndicat Mixte du 

Bassin Versant du Vistre" to increase the ecological functioning of the river. Among the 

management operations, the reduction of the invasion of L. peploides has been undertaken since 

2008 by mechanical and manual removal. 

In 2008, 5 km of river were managed and the volume of removed plants was 173 m 3 of wet 

plants, with about 100 m 3 mechanically removed, for 75 work days. In 2009, the length of 

managed river increased to 14 km in other parts of the river and in its affluents with 152 m 3 of 

manually removed plants for 85 work days. Several sites managed in 2008 showed little 

recolonization by the invasive plant. 

A long term management of this plant is necessary to minimize all impacts of L. peploides and 

insure better ecological functioning of the river in the context of the European Water Framework 

Directive. 

Posters 


393

Control and local eradication of Ailanthus altissima in a river Park in Northern Italy 

Anna Mazzoleni 1 , Elena Tironi 1 , Eric Spelta 1 , Gianluca Agazzi 2 , Federico Mangili 2 , Gabriele 

Rinaldi 2 

1 

Parco del Basso Corso del Fiume Brembo (www.parcobassobrembo.it; E-mail: 

info@parcobassobrembo.it) 

2 

Bergamo Botanical Garden (www.ortobotanicodibergamo.it; E-mail: 

ortobotanico@comune.bg.it) 

Introduction 

The ―Parco del Basso Corso del fiume Brembo‖ park was instituted by 7 

municipalities along the Brembo River, in Northern Italy, Region of 

Lombardia. The Park covers nearly 10 km 2 of the river floodplain and is 

situated in one of the most populated and urbanized areas in Europe. Despite 

the impact of urbanization, the Park conserves natural environments including 

semi-natural dry grasslands and riparian forests, habitats that are rich in rare 

herbaceous plants. The safeguard of these residual environments is essential 

both in protecting the ecosystem biodiversity of Brembo River and in 

contributing to the resident population‘s lifestyle. The increasing spread of the 

invasive alien tree Ailanthus altissima in the Park is favoured by the closely 

interwoven hydrographic network crossing the Park and is threatening the 

conservation of its natural habitats, in particular semi-natural dry grasslands. 

Consequently, the eradication (in selected localised areas) and control of A. 

altissima became one of the primary aims of the Park‘s management. A six year 

long experimental project was initiated and co-financed with regional funds. 

The project, started in August 2010, is focused on chemical treatments and 

involves the use of low-impact techniques such as stem injection, localized 

treatment of cut stump and basal bark. The herbicide (a combination of 

triclopyr and fluroxipyr) has been chosen as the most selective and least 

impacting on natural environment, among the formulations registered in Italy 

for use on woody plants. The efficacy of the treatments and their effect on the 

environment will be monitored, with the purpose of defining and 

communicating a procedure for the efficient and sustainable managing of A. 

altissima in protected areas of Northern Italy. Strategic guidelines will also 

include ongoing prevention of new potential infestations, through education 

programmes and the involvement of local administrations, farmers and citizens. 

The increasing spread in the environment of invasive alien plants is a serious threat to nature 

conservation and land management, especially in the case of protected areas. 

The tree Ailanthus altissima (tree of heaven) is a very common species of the Italian alien flora 

and it is considered invasive in the whole Country (Celesti-Grapow et al., 2009; 2010a, 2010b) in 

Europe and in the rest of the world (e.g. Aldrich et al., 2008). 

According to Aldrich et al. (2008) it incorporates many of the strategies employed by invasive 

species including (a) early and prolific seed production (Feret 1973) as a single adult can produce 

more than 300,000 seeds in a year (DAISIE 2006), (b) long-distance seed dispersal (Matlack 

Posters 


394

1987), (c) aggressive clonal reproduction (Miller 1990, 2000), and (d) a reliance on high sunlight 

(Grime and Jeffrey 1965). Moreover, (e) Ailanthus produces toxins that inhibit plant growth and 

appear to render it unpalatable to many herbivores (Heisey 1990a, b, 1996; De Feo et al. 2003). 

For a recent review of the biology of Ailanthus altissima see Kowarik and Sämuel (2007), and for 

its impact on Mediterranean islands Vila et al. (2006). 

Its spread in the ―Parco del Basso Corso del Fiume Brembo‖ park is threatening the 

conservation of natural and semi-natural residual habitats (in particular dry grasslands) and is 

fuelled by the dense hydrographical network crossing the Park. 

Ailanthus altissima, well adapted to rocky substrates which limits the growth of other tree 

species, behaves as a pioneer plant onto the soils of the Brembo river floodplain. In the absence 

of interspecific competition, it can colonize grasslands growing in thick monospecific clusters. 

Moreover, the allelopathic substances produced by the roots of A. altissima cause the total 

disappearance of herbaceous species from the infested areas, with huge damages to biodiversity. 

The conservation of these residual environments is essential both to the protection of biodiversity 

in Brembo River ecosystem and to the quality lifestyle of the resident population. In fact, the 

inhabitants are increasingly requiring the presence and maintenance of natural areas. 

Consequently, the control and eradication of A. altissima in the natural habitats of Brembo River 

floodplain became a priority issue for the Park management which, according with the local 

administrations, developed an experimental six-year long project focused on this topic. 

Site description 

Parco del Basso Corso del Fiume Brembo is a park instituted by 7 municipalities along 

Brembo River, in the Region of Lombardia in Northern Italy. The park covers nearly 10 km 2 of 

the river floodplain and is included in one of the most populated, urbanized and industrialized 

areas in Europe (Table 1). 

Table 1 - Land surface and population of the municipalities of the Park of Brembo River 

Municipality Inhabitants Municipality 

area (km 2 Demographic Park 

density 

area 

) 

(inhabitants/km2) (km 2 ) 

Park area on 

municipality 

area (%) 

Boltiere 5,402 4.13 1,308 0.93 22.52% 

Bonate Sotto 6,404 6.36 1,007 2.39 37.58% 

Dalmine 22,741 11.96 1,901 1.34 11.20% 

Filago 3,138 5.45 576 2.13 39.08% 

Madone 3,911 3.06 1,278 0.69 22.55% 

Osio Sopra 4,959 5.16 961 0.98 18.99% 

Osio Sotto 11,279 7.66 1,472 1.29 16.84% 

Total 57,834 43.78 1,321 9.75 22.27% 

Despite the impact of urbanization the Park contributes significantly to semi-natural dry 

grasslands and riparian forests which contain, among others, rare herbaceous communities. Dry 

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grasslands, along the river‘s banks, host rare and valuable species, almost disappeared in the rest 

of the Region. The plant community is described by Directive no.92/43/CEE ―Habitat‖ as 

―Natural and Semi-natural dry grasslands and scrubland facies on calcareous substrates (Festuco- 

Brometalia)” - habitat 6210. This is a priority type habitat due to its richness of orchids (EC 

2007a), such as Orchis coriophora, O. morio, O. tridentata, Ophrys fuciflora, Spiranthes spiralis. 

A survey aiming to evaluate the extent of A. altissima invasion was made by the Voluntary 

Ecologic Guardians of the Park in 2007. Over 1 invaded km 2 was recorded in the Park and its 

surroundings. In this area A. altissima provides mainly clonal populations, presenting infestation 

nucleus of 15-20 years old trees surrounded by large clusters of young rootsprouts. A little 

number of trees seeds producing was found. 

It appeared that invaded areas are located mainly along the riparian network and in proximity 

of construction sites, where soil has been disturbed or imported from external areas. This can be 

interpreted as a demonstration that urbanizing dynamics, as road buildings, continuously 

occurring near and across the Park, enhance the spread of invasive plants inside the Park habitats 

by disturbing the stability of the soils. 

The project on invasive alien plants: aims and description 

In 2009, the Park management developed a pilot project to control invasive alien plants in the 

Park and a regional fund of 230,000.00 Euros was allocated. 

This project was effective in 2010 and is conceived to run six years. 

Its aims are: 

- The eradication of Ailanthus in the Park (priority areas) and the restoration of original 

habitats; 

- The definition and the testing of a procedure for an efficient and sustainable management 

of A. altissima to be possibly shared with neighbouring municipalities and institutions. 

A procedure is considered ―environmentally sustainable‖ when it produces positive effects on 

native biodiversity and ―economically sustainable‖ if it can be supported by the local available 

resources. The project aims to define firstly an environmentally sustainable procedure. The 

economical sustainability can be reached through a large scale cooperation, actually often 

lacking. 

Since funding and other available resources were not sufficient to manage all the invaded areas, a 

selection of priority sites for intervention was required. The prioritization criteria were as 

follows: 

- The ecological fragility and environmental richness of the invaded habitats; 

- The site proximity to watercourses, as these networks are important routes for the spread 

of Ailanthus altissima seeds. 

A total of 70,000 m 2 of heavily invaded land (up to 10 stems/ m 2 ) had been identified as 

priority areas, on which the massive control of Ailanthus altissima will be activated. 

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Control and eradication methods 

Experimental evidences reported in international literature prescribe chemical treatments as 

the most effective technique able to control Ailanthus altissima (Burch and Zedaker 2003, 

Meloche and Murphy 2006, DiTomaso and Kyser 2007). Direct observations and experimental 

trials in the project sites confirmed this finding. 

Therefore, the project involves the use of chemical treatments applied through low-impact 

techniques as stem injections, localized treatment of cut stump and basal bark. The herbicide used 

is a systemic formulation combining triclopyr and fluroxipyr. This herbicide has been chosen as 

the most selective and least impacting on natural environment, among the formulations registered 

in Italy for use on woody plants. Moreover, the seeds found in the project sites are collected by 

hands and destroyed. 

Project cycle and management problems 

Several difficulties are expected to interfere with the project aims and have to be addressed. 

First of all, it is very important to verify the effects of the chemical treatments on native flora. 

For this purpose, the project includes ongoing environmental monitoring, led and performed by 

Bergamo Botanical Garden. The monitoring focuses on sample areas, selected on the basis of A. 

altissima population typology and the presence of indicator species and rare species. Floristic 

surveys following the treatment will be conducted for a period of 3 years in order to evaluate 

changes in biodiversity. 

As already stated, the Park area belongs to 7 different local communities, interesting the 

lowest part of the course river. Considering the whole extension of the river course, the number 

of territorial institutions increases to several tens. This implies a fragmentation of land 

management and, lacking an over-local coordination, limits the effectiveness of the localized 

treatments. Therefore, the project aims to involve neighbouring parks and municipalities; in 

particular, it looks necessary to control the seeds production in the invaded areas upstream 

located, for preventing and limiting the new seedlings colonisations in the treated areas. That 

notwithstanding, new outbreaks of A. altissima are to be expected in the Park‘s area even after 

the project conclusion, due both to seeds brought by the watercourses from the invaded upstream 

areas and to the construction works which cause soil displacement from untreated areas to other 

sites. 

Another hindrance is the prevalence of private property land in the Park, including the priority 

areas. The control of invasive alien plants, in case of A. altissima, is not considered a work of 

public interest: consequently municipalities cannot enforce it. The voluntary involvement of land 

owners is therefore necessary in order to reach the project aims. Information campaigns and 

education programs, addressing citizens, farmers and land owners, appear to be essential 

instruments to raise potential stakeholders‘ awareness and facilitate their approval and 

cooperation to the project. 

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Conclusions 

A definitive eradication of A. altissima inside the Park of Brembo River appears to be very 

difficult because its territory suffers the negative effects of the neighbouring urbanized areas. On 

the other side, a strategy of control and management of A. altissima looks to be possible and 

necessary to the safeguard of the Park‘s habitats. 

The project is not only designed to control this invasive alien plant in the territory of the Park, 

but also stands up as a pilot-project, with the purpose of defining and communicating a tested 

procedure for the efficient and sustainable management of A. altissima in sensitive areas of 

Northern Italy. The environmental monitoring carried out by the Bergamo Botanical Garden will 

give information about the effect on biodiversity of the tested procedure and will measure its 

environmental sustainability. 

The proximity of the Park to important urban and industrial centers is the main cause of its 

ecological fragility but, in the meantime, it poses also its surplus value, because the local citizens 

and civil associations are showing an increasing sensitiveness to environmental issues and can be 

easily involved in the Park‘s safeguard programs. Their involvement is very important for 

reducing the costs and reaching the goal of economical sustainability. For example, the early 

detection of new infestations can be carried out by the team of Voluntary Ecologic Guardians of 

the Park, without additional costs. Subsequently, the Park management will devise ongoing 

programs aimed to rapid response to new infestations. 

Nevertheless, it is necessary to underline that an effective and economically sustainable 

strategy for A. altissima control requires the involvement of a network of institutions (inside and 

outside the target area), the cooperation of the resident population and the adaptation of the law, 

for instance through enforcing a regulation of the soil movements and permitting the eradication 

of invasive alien plants in private areas even without the owner‘s permission. 


We gratefully acknowledge the Mayors, administrators, officers and Voluntary Ecologic 

Guardians of the municipalities of the Park for actively supporting the project development; 

Mr Leonardo Bacci (Dow-AgroScience-Italy) for providing precious technical information and 

suggestions about chemical treatments in natural areas; Ms Paola and Elisabetta Mangia for 

improving and correcting our English. 

References 

Aldrich PR, Brusa A, Heinz CA, Greer GK & Huebner C (2008) Floral Visitation of the Invasive Stinking Ash in 

Western Suburban Chicago. Transactions of the Illinois State Academy of Science 101, 1-12. 

Blasi C (2010) Non-native flora of Italy: species distribution and threats. Plant Biosystems 144(1): 12-28. 

Burch PL & Zedaker SM (2003) Removing of invasive tree Ailanthus altissima and restoring natural cover. Journal 

of Arboriculture 29(1), 18-24. 

Celesti-Grapow L, Alessandrini A, Arrigoni PV, Banfi E, Bernardo L, Bovio M, Brundu G, Cagiotti MR, Camarda I, 

Carli E, Conti F, Fascetti S, Galasso G, Gubellini L, La Valva V, Lucchese F, Marchiori S, Mazzola P, 

Peccenini S, Poldini L, Pretto F, Prosser F, Siniscalco C, Villani M.C, Viegi L, Wilhalm T & Blasi C (2009) 

The inventory of the non-native flora of Italy. Plant Biosystems 143, 386-430. 

Celesti-Grapow L, Pretto F, Carli E & Blasi C (eds.) (2010b) Flora alloctona d‘Italia. CD-ROM. Allegato a Celesti- 

Grapow L. et al. (eds.) Le invasioni di specie vegetali in Italia. Palombi, Roma. 

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DAISIE (2006) Ailanthus altissima facsheet. Basnou C. & Vilà M. (eds). Available at: http://www.europealiens.org/pdf/Ailanthus_altissima.pdf 

[Accessed 30 September 2010]. 

De Feo V, De Martino L, Quaranta E & Pizza C (2003) Isolation of phytotoxic compounds from Tree-of-Heaven 

(Ailanthus altissima Swingle). Journal of Agricultural and Food Chemistry 51, 1177-1180. 

DiTomaso JM & Kyser GB (2007) Control of Ailanthus altissima using stem herbicides application techniques. 

Arboriculture & Urban Forestry 33(1), 55-63. 

Feret PP (1973) Early flowering in Ailanthus. Forest Science 19, 237-239. 

Grime JP & Jeffrey DW (1965) Seedling establishment in vertical gradients of sunlight. Journal of Ecology 53, 621- 

642. 

Heisey RM (1996) Identification of an allelopathic compound from Ailanthus altissima (Simaroubaceae) and 

characterization of its herbicidal activity. American Journal of Botany 83(2), 192-200. 

Heisey RM (1990a) Allelopathic and herbicidal effects of extracts from tree of heaven (Ailanthus altissima). 

American Journal of Botany 77, 662-670. 

Heisey RM (1990b) Evidence for allelopathy by tree-of-heaven (Ailanthus altissima). J. Chem. Ecol. 16, 2039-2055. 

Kowarik I & Sämuel I (2007) Biological flora in central Europe: Ailanthus altissima (Mill.) Swingle. Perspectives in 

Plant Ecology. Evolution and Sistematics 8, 207-237. 

Matlack GR (1987) Diaspore size, shape, and fall behavior in wind-dispersed plant species. American Journal of 

Botany 74, 1150-1160. 

Meloche C & Murphy SD (2006) Managing tree-of-heaven (Ailanthus altissima) in parks and protected areas: a case 

study of Rondeau Provincial Park (Ontario, Canada). Environ. Manage 37, 764-772. 

Miller JH (1990) Ailanthus altissima (Mill.) Swingle ailanthus. In: Burns, R. M., and B. H. Honkala (Tech. coords.) 

Silvics of North America: Vol. 2. Hardwoods. Agriculture Handbook 654. Washington, DC, US Department 

of Agriculture, Forest Service, pp. 101-104. 

Miller JH (2000) Ailanthus altissima. USDA Forest Service. [http://willow.ncfes.umn.edu/ silvicsmanual/ 

volume_2/ailanthus/altissima.htm]. 

Vilà M, Tessier M, Suehes CM, Brundu G, Carta L, Galanidis A, Lambdon P, Manca M, Médail F, Moragues E, 

Traveset A, Troumbis AY & Hulme PE (2006) Local and regional assessment of the impacts of plant invaders 

on vegetation structure and soil properties of Mediterranean islands. Journal of Biogeography 33, 853-861. 

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Solanum elaeagnifolium, an increasing problem in Greece 

Eleni Kotoula-Syka 

Democritus University of Thrace. E-mail: kotoulaeleni@yahoo.gr 

Introduction 

Silverleaf nightshade (Solanum elaeagnifolium), is thought to be native to the 

southwestern USA and northern Mexico. It was observed in California before 

1900 and in Greece before 1975. During the last 20 years this troublesome 

weed has spread in all Greece, especially Thessaloniki and Chalkidiki counties 

because of the intensive human activities (constructions of new roads, buildings 

or agricultural activities). Most fields with arable, horticultural and perennial 

crops as well as waste places and roadsides have been infested by this weed. S. 

elaeagnifolium foliage has star shaped hairs. Mature berries contain high levels 

of solanine and solanosine, which are toxic to livestock. Large infestations can 

reduce harvest yields by competing with desirable plants of nutrients and soil 

moisture, and have allelopathic effects especially in cotton fields. Plants 

develop colonies from extensive systems of creeping horizontal and deep 

vertical roots, both of which produce new shoots. Flower clusters are modified 

cymes the lower flowers are bisexual and the upper ones are functionally male. 

Seeds are yellowish-brown to dark yellow-brown. The plant blossoms from 

May to September with light to dark blue-lilac or white color flowers. Silverleaf 

nightshade reproduces by seeds and creeping roots. Fruits and seeds disperse 

with agricultural activities, water, mud, soil movement and animals. Colonies of 

silverleaf nightshade are difficult to control by mechanical methods or by 

biological means because there is currently no registered biocontrol agent for 

use against this plant. In Greece the only method used against silverleaf 

nightshade in irrigated summer and perennial crops consists in weekly mowing 

that prevents the production of new shoots or the establishment of new 

seedlings during summer months. However, this practice does not solve 

permanently the problem, as shallow cultivation does not disturb enough the 

root system while it increases the problem by dispersing rhizome fragments in 

non contaminated areas. 

Solanum elaeagnifolium Cav., silverleaf nightshade, is considered native to southwestern USA 

and northern Mexico. It was introduced from US during the 40s and was recorded in Greece for 

the first time before 1975. 

Since the last 20 years this troublesome weed has spread in all Greece, especially in the 

Thessaloniki and Chalkidiki counties because of the intensive human activities (constructions of 

new roads, buildings or agricultural activities). 

This plant usually grows in places disturbed by people of livestock, especially those with a 

high summer moisture or irrigation. The plant can tolerate considerable drought because if its 

deep root system. Silverleaf nightshade colonizes fields, roadsides, agronomic and vegetable 

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crops, especially cotton and tomatoes, orchards, vineyards, pastures, rangeland, forest openings, 

waste places. It grows best on light sandy soils, but tolerates most soil types, except those subject 

to flooded conditions. Most fields in the above mentioned counties, with arable, horticultural and 

perennial crops as well as waste places and roadsides have been infested by this weed. 

Foliage and berries of this species, contain variable amounts of several glycoalkaloids and can 

be toxic when ingested by livestock or people. Dried plant material does not lose its toxicity. 

Finally, this plant is an alternative host for disease and insect pests for a broad range of crops in 

Greece. 

Silverleaf nightshade can be troublesome in agricultural fields and pastures, especially those 

receiving summer irrigation. It may reduce crop yields through direct competition for resources. 

Large infestations can reduce harvest yields or crops and the carrying capacities of pasture by 

competing with desirable plants of nutrients and soil moisture. There are also indications of 

allelopathic effects on several important crops especially in cotton fields. 

In this paper, plant features and control methods of silverleaf nightshade are presented. The 

aggressiveness and difficulties of containment of this species are discussed. 

Plant traits 

Solanum elaeagnifolium Cav. is a perennial erect herb to sub- shrub with creeping roots which 

reaches the height of 1 m. Prickles straight, fine, often reddish, some times yellowish, to about 5 

mm long, sometimes lacking on stems, often lacking on leaf veins. Leaves dull silvery-to pale 

yellowish-green from dense covering of star-shaped hairs. Fruits contain solanosine, a steroid 

compound used commercially to synthesize steroid hormones. New shoots from roots resemble 

seedlings, but lack of cotyledons. Silverleaf nightshade cotyledons are narrowly lanceolate to 

elliptic. Upper surfaces glossy green, lower surface light green. Stalk below cotyledons 

(hypocotyl) often purple-tinged, covered with short, stiff, downwards pointing hairs. 

Plants develop colonies from extensive systems of creeping horizontal and deep vertical roots, 

both of which produce new shoots. Horizontal roots can extent outwards to 1 m or more before 

developing new shoots. Vertical roots can penetrate soil to depths of 2 m or more. Roots store 

large quantities of carbohydrates and have a high regenerative capacity. Silverleaf nightshade 

roots can generate shoots from soil depths to 50 cm. Fragments 1 cm long can regenerate from 

depths of 20 cm or more in loose moist soil. Regeneration depths for small root fragments are 

much less in dry, saturated, or heavy soils. Root fragments tolerate some desiccation, but not 

freezing. Silverleaf nightshade fragments (5 cm long) can survive for up to 15 months under 

moist conditions. 

The weed flowers from May to September. Flower clusters are modified cymes (oldest flower 

at tip of main axis). Often lower flowers are bisexual while upper flowers have reduced female 

parts and are functionally male. Corona star-shaped, 5-lobed. Sepals lack prickles. Anthers erect, 

longer than filaments, spreading or loose around style. 

Seeds yellowish-brown to dark yellow-brown, 2,5-3,5 mm long, 1,8-2,5 mm wide, smooth 

semiglossy. 

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Foliage of silverleaf nightshade dies back after the first fall frost, and dead stems may persist 

for several months, loosing prickles and having a few wrinkled yellowish fruits. 

The weed reproduced by seeds and vegetatively from creeping roots. Fruits and seeds are 

dispersed by agricultural activities, water, mud and soil movement, and animals. Root fragments 

are dispersed primarily by cultivation or other human activities. In winter, roots of silverleaf 

nightshade go dormant and foliage dies back. Roots generate new shoots in spring. Seeds 

germinate spring through summer, and berries mature in 4-8 weeks. Each berry might contain up 

to 76 seeds. Seeds are typically highly viable, but germination is often sporadic from year to year. 

Three to 10 year old seed can have higher germination percentages than newly matured seed. 

Factors controlling seed germination are poorly understood. Fluctuating temperatures appear to 

play a role. Seed is coated with a mucilaginous material that may inhibit germination until it is 

leached or degraded. Seed ingested by animals often survives and is more likely to germinate. 

Under favourable conditions, seed germination percentages can be high (about 80%). Seed can 

remain viable for at least 10 years. 

Control methods 

There are few control options against S. elaeagnifolium: prevention, mechanical, biological 

and chemical control methods. 

Infestations should be promptly controlled to prevent further spread. Clean equipment before 

leaving contaminated fields, and avoid spreading root fragments by cultivation equipment. Check 

hay for nightshade berries, before feeding to cattle. This will prevent both livestock poisoning 

and the introduction of seed into uninfected areas. 

Silverleaf nightshade can regenerate from root cuttings of less than 1 cm in length. Tillage 

may spread rootstocks to new areas, where establishment can occur. Small infestations may be 

hand pulled or hoed, but control has to be repeated several times during the growing season. Any 

root material that is dug should be collected, dried and burnt. Repeated mowing through the 

summer may nearly eliminate seed production. However, the plants will take on a flat, rosettelike 

growth form that is capable of replenishing root carbohydrate reserves. 

The nematode, Orrina phyllobia, is most specific for silverleaf nightshade. Augmentative 

releases of this nematode may eventually help reduce populations. However, these are no 

currently registered biocontrol agents for use on silverleaf nightshade. 

Few herbicides effectively control silverleaf nightshade and their application is dependent 

upon the land use. Herbicides should be applied late bud to early flower. Glyphosate in a 2% 

solution can be applied as a spot treatment. Dicamba and 2,4-D can be applied at 0.5-1.0 and 1.0- 

2.0 lb ae/A, respectively. Triclopyr can be applied at 1-3 ib ae/A. Regrowth will occur with any 

of these treatments and retreatment will be necessary. Picloram has provided excellent control of 

this species, but is not currently labeled for this reason while clopyralid has not provided good 

control of silverleaf nightshade. 

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Gyphosate is a non-selective herbicide and will injure or kill any foliage it contacts. Dicamba, 

2,4-D, and triclopyr will injure or kill most other broadleaf plants. These factors should be 

considered when applying these herbicides. 

Conclusions 

Colonies of S. elaeagnifolium with creeping roots are difficult to control or eliminate by 

mechanical methods in Greece as in other agricultural areas in the invaded range. Shallow and 

deep tillage does not disturb enough of the root system to eliminate infestations and can increase 

the problem by dispersing root fragments. Deep ripping under dry conditions may reduce but 

typically does not eliminate infestations of silverleaf nightshade. Weekly mowing prevents most 

seed production and can help weaken roots by reducing carbohydrate reserves, but does not 

eliminate infestations. Confine livestock from infected pasture for 6-7 days before moving 

animals to uninfected areas prevent introduction of seed. It is clear that more comprehensive and 

integrated approach requires containing this invasive alien plant. 

References 

Boy JW & Murray DS (1982) Growth and development of silverleaf nightshade (Solanum elaeagnifolium). Weed 

Science 30, 238-243. 

Eleftherohorinos IG, Bell CE & Kotoula-Syka E (1993) Silverleaf nightshade (Solanum elaeagnifolium) control with 

foliar herbicides. Weed Technology 7, 808-811. 

Green JD, Murray DS & Verhalen LM (1987) Full-season interference of silverleaf nightshade (Solanum 

elaeagnifolium) with cotton (Gossypium hirsutum). Weed Science 35, 813-818. 

Parker PE (1986) Nematode control of silverleaf nightshade (Solanum elaeagnifolium); a biological control pilot 

project. Weed Science 34, 33-34. 

Westerman RB & Murray DS (1994) Silverleaf nightshade (Solanum elaeagnifolium) control in cotton (Gossypium 

hirsutum) with glyphosate. Weed Technology 8, 720-727. 

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Plant invasion, soil seed banks and native recruitment in two urban Mediterranean 

woodland remnants, in South-West Australia 

Judith L. Fisher 1 & Roberto Crosti 2 

1 School of Plant Biology University of Western Australia / Fisher Research, PO Box 169, 

Floreat, Perth, Western Australia 6014, Australia 

E-mail: ecologist@waanthropologist.com (Corresponding author) 

2 ISPRA- Dipartimento Difesa della Natura-Tutela biodiversità, Via Curtatone 3 00185 ROMA, 

Italy 

E-mail: roberto.crosti@isprambiente.it 

The Mediterranean South-West of Australia is listed within the world‘s 25 biodiversity hot spots 

where fire is important for the persistence and stability of plant communities. The dominant 

Banksia woodland is a complex fire adapted ecosystem, has a diversity of plant functional 

groups, with highly complex species interactions required to maintain ecological processes and 

resilience to disturbance. The diversity of life forms is critical for ecosystem renewal and 

reorganization following disturbance, providing a mechanism for resistance to change. An 

association has been found between structural and functional changes in plant community 

assembly and the frequency of fire and invasion, in two urban woodland remnants of Kings Park 

and Bold Park, in Perth southwest Australia. Soil seed bank studies, in situ and ex situ, and native 

recruitment studies, with and without invasion, have been conducted and provide an 

understanding of the plant communities‘ response to invasive species. The results of these studies 

have been utilised to determine new and effective management intervention techniques resulting 

in the conversion of a plant community once dominated by transformer invasive species to a 

resilient native plant community. 

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404

Applying cover crops to reduce impacts of Orobanche spp. in infested fields 

Mitra Ghotbi 1 , Marjan Ghotbi 2 & Ahmet Uludağ 3 

1* 

Department of Agronomy, Agriculture Faculty, Shahed University, Tehran, Iran E-mail: 

mitra.ghotbi@gmail.com 

2 

European Environment Agency, Faculty of Natural Resource and Agriculture, Science & 

Research branch of Azad University, Tehran, Iran 

3 

Igdir University, Faculty of Agriculture, Igdir, Turkey 

Introduction 

Broomrapes (Orobanche spp.) are aggressive and damaging parasitic weeds 

which have a tremendous impact on agriculture in East Africa, the 

Mediterranean region besides the Middle East. Management with herbicides is 

partially effective; thus, non- chemical economical methods such as using 

cover crops could be an effective way to prevent broomrape from spreading. 

To achieve this aim, having the knowledge of the host range including hosts, 

false hosts or non-host seems essential. Through the current review; Host 

categories besides their impacts as cover crops to decline infestation of 

broomrape were investigated. Cover crops besides exerting a strong influence 

on weed infestation may have an impact on water availability, soil 

improvement and yield of the cultivated crops in the rotation. Several studies 

have defined cotton as a trap crop which is not only can increase tomatoes 

yield but also would be able to alleviate Orobanche aegyptiaca infestation. 

Substituting sufficient cover crops with chemo-herbicides which are cheaper as 

well as more effective than other attempts could be rational method to pursue. 

Overall, if even prevention measures are taken to limit the spreading of these 

parasitic weeds we constrict Orobanch complaints in infested territories. 

Broomrapes (Orobanche spp.) are aggressive and damaging parasitic weeds which have a 

tremendous impact on agriculture in East Africa, the Mediterranean region besides the Middle 

East. 

Most of the species attacked by Orobanche belong to the Asteraceae (20 species), Fabaceae 

(9 species), Rosaceae and Chenopodiaceae (7species) (Romanova et al., 2001; Abanga et al., 

2007). Currently, there is no consistent and sustainable method for the control of Orobanche 

(Goldwasser & Kleifeld, 2004). Crop rotation with trap (Ross et al., 2004) and catch (Acharya et 

al., 2002) has long been proposed and practiced as control measure for broomrape in infested 

soil. Like et al. (1989) reported a 30% reduction in the crenata broomrape (Orobanche crenata 

Forsk.) seedbank after one catch crop cycle. In Oregon, USA, wheat (Triticum aestivum L.) was 

reported to be a false-host of O .minor (Ross et al., 2004), and therefore, has the potential to be 

implemented in to an integrated O.minor management system. Sorghum (Sorghum Vulgare 

pers.), maize (Zea mays L.), mung been (Phaseolus aureus Roxb.) and cucumber (Cucumis 

sativus L.) have been mentioned as trap crops for O. ramosa (Parker and Riches,1993) and sweet 

pepper has been reported as a trap crop for Egyptian broomrape. Flax (linseed) has been cited as 

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an efficient trap crop for O. crenata Forsk., O. crenua Loefl. and O. ramosa (Krishnamurty et 

al., 1977). 

Applying Cover Crops in rotation against brοοmrape 

Rotation may have direct and indirect impacts on parasitic plants in infested areas. Some 

legume crops increase soil fertility that contributes to the ability of susceptible crops to compete 

with their parasites. The increase in soil fertility may also stimulate a reduction of the secretion 

of germination stimulants by the crop roots (Yoneyama et al., 2007). 

Asteraceae: Sunflowers, safflower alsoconeflowers, goldenrods, and many other crops belong to 

this family. It is one of the important families among those which are attacked by 

Orobanchaceae (Sauerborn et al., 2007; Qasem & Foy, 2007). 

Poaceae: These crops are often grown to produce income, but they also make excellent cover 

crops due to the many ecological benefits they provide to the farming system. They establish 

quickly, produce high biomass and dense fibrous root systems (to prevent soil erosion, sequester 

carbon, increase soil organic matter content, and improve soil quality), and can scavenge and 

store available soil nutrients. Allelopathic substances from Rye, Sorghum and other cover crops 

have been shown to inhibit the emergence and early growth of many weeds (Abebe et al., 2005; 

Clark 2007). 

Malvaceae: Cotton (Gossypium hirsutum L) in Malvaceae family is a dominant example of trap 

crops utilization. It is the source of the first isolated germination stimulant strigol, probably for 

all Orobanche and Phelipanche species (Fernandez-Aparicio et al., 2008). Moreover, since 

cotton can be grown in a variety of soils from light sandy soil to heavy alluvium and calcareous 

clay, in addition to its tolerance to salt it is an efficient plant to apply as a cover crop in rotation 

for most territories. 

Fabaceae: Legumes are a large group of plants in the bean family (Fabaceae). Most plants in 

this group have a beneficial relationship with specific soil bacteria (Rhizobium spp.). Legumes 

can produce substantial biomass, attract beneficial insects, suppress weeds through competition 

and in some cases, allelopathy through intercropping methods (Abebe et al., 2005; Clark, 2007). 

Conclusion 

Trap crops probably cannot completely eliminate the O. aegyptiaca soil seedbank in a single 

cycle (Lins et al., 2006). With this in mind, integrated management of O. aegyptiaca must be 

utilized to broaden the focus of control strategies. Flax in Linaceae family which has been 

suggested by many investigators as a trap crop for Orobanche (O. ramosa; O. cernua; O. 

crenata), was severely parasitized by O. aegyptiaca. So utilizing flax as a trap crop in rotation 

can decline O. aegyptiaca infestation in soil. Clover was suggested as a trap crop by Al-Menoufy 

(1989) for O. crenata, mung bean was suggested by Krishnamurty et al. (1977) for O. crenua; 

both were heavily parasitized by O. aegyptiaca. Ten potential trap crops from different crop 

families were examined by Abebe and his colleagues (2005) Fenugreek (Trigonella foenumgraecum), 

Linseed / Flax (Linum usitatissimum), Alfalfa (Lucern), Cotton (Gossipium spp), 

Onion (Allium spp), Garlic (Allium sativum), Pepper (Capsicum annum), Snap bean (Phaseolus 

vulgar), Maize (Zea mays), Sesame (Sesamum indicum), Tomato (Lycopersicum esculentum) as 

a (Check). They defined that Maize (Zea mays) in Poaceae family and Snap bean (Phaseolus 

vulgare) in Fabaceae family between others remarkably reduced soil seed bank of O. ramose and 

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406

O. cernua by 74 and 71%, respectively. Subsequently, they concluded that the Orobanche shoot 

count was significantly reduced for trap crop planted plot than the check and tomato yield was 

increased as a result of reduction of Orobanche shoot count (Abebe et al., 2005). Fernandez- 

Aparicio reported that cotton (Gossypium hirsutum L.) (the source of the first isolated 

germination stimulant strigol) probably for all Orobanche, Phelipanche species, linseed (Linum 

usitatissimum) for P. ramosa and P. aegyptiaca, mungbean (Phaseolus aureus) for P. 

aegyptiaca, Egyptian clover (Trifolium alexandrinum L.) for O. crenata, sunhemp (Crotalaria 

juncea) and mung bean (Vigna radiata) for O. cernua rolled as trap crops. Fenugreek stimulates 

P. ramosa seed germination, but not the seeds of O. foetida; O. crenata seed germination is 

inhibited (Fernandez-Aparicio et al., 2008), which all given traps can mitigate Orobanche and 

Phelipanche infestation in field. 

Discussion 

Climate change by which parasite seeds are transferred from one place to another place into 

the hands of the parasites and may soon lead to a broomrape ‘‘epidemic‘‘ in many other 

countries as well. If care is not immediately taken to limit the introduction of parasitic weed 

seeds and to educate farmers and others to be on alert for new infestations, large areas of new 

territory will be at risk of invasion (Grenz & Sauerborn, 2007). Based on the current knowledge 

of the weedy Orobanche and Phelipanche species, scientists strongly believe that, early 

prevention of the problem include of using suitable crop sequence is much cheaper and more 

effective than a late effort to control the parasites in the field (Rubiales et al., 2009). 

References 

Abebe G, Sahile G & Al-Tawaha ARM (2005) Evaluation of potential trap crops on Orobanche soil seed bank and 

Tomato yield in the central rift valley of Ethiopia. World Journal of Agricultural Sciences. 2, 148-151. 

Abanga MM, Bayaaa B, Abu-Irmailehb B & Yahyaouia A (2007) A participatory farming system approach for 

sustainable broomrape (Orobanche spp.) management in the Near East and North Africa. Crop Protection 

26, 1723-1732. 

Acharya BD, Khattri GB, Chetri MK & Srivastava SC (2002) Effect of Brassica campestris var. toria as a catch crop 

on Orobanche aegyptiaca seed bank. Crop protection 21, 533-537. 

Al-Menoufy OA (1989) Crop rotation a control measure of Orobanche crenata in Vicia faba fields. In: Wegmann 

K& Musselman LJ, eds. Prgrress in Orobanche Research. Germany: Eberhard-Karl-Universitat Tubingen, 

241-7. 

Clark A (2007) Managing cover crops profitably.Handbook Series 9 Published by the Sustainable Agriculture 

Network, Beltsville, MD 233. 

Ferna´ Ndez-Aparicio M, Andolfi A, Evidente A, Pe´ Rez-Deluque A & Rubiales D (2008) Fenugreek root 

exudates show species-specific stimulation of Orobanche seed germination. Weed Research. 48, 163-168. 

Goldwasser Y& Kleifeld Y (2004) Recent approaches to Orobanche management: a review In: Weed Biology and 

Management (ed. Inderjit), 439-466. Kluwer Academic Publishers, Dordrecht, Germany. 

Kleifeld Y, Goldwasser Y, Herzlinger G, Joel DM, Golan S & Kahana (1994) The effects of flax (Linum 

usitatissimum L.) and other crops as trap and catch crops for control of Egyptian broomrape (Orobanche 

aegyptiaca Pers.) Weed Res. 34, 37-44. 

Krishamurty GVG, Lar R & Nagaraja K (1977) Further studies on the effect of various crops on the germination 

Orobanche seeds. Pest Articles and News Sum 23, 206-8. 

Lins RD, Colquhoun JB & Mallory-Smith CA (2006) Investigation of wheat as a trap crop for control of Orobanche 

minor, Weed Research. 46, 313-318. 

Parker C, Riches CR Parasitic (1993) Weeds of the World: biology and Control, CAB International, Wallingford, 

UK, 111-164. 

Qasem JR and Foy CL (2007) Screening studies on the host range of branched broomrape (Orobanche ramosa). J. 

Hort. Sci. Biotech. 82, 885-892. 

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407

Romanova V, Teryokhin E & Wegmann K (2001) Investigation of intraspecific taxonomy in Orobanche cernua 

Loefl. By the method of biological tests. Age 80 in Fer A, Thalouarn P, Joel DM, Musselman LJ, Parker C & 

Verkleij AC, eds. Proceeding of the 7th International Parasitic Weed Symposium; Nantes, France: University 

of Nantes. 

Ross KC, Colquhoun BJ & Mallory-Smith CA (2004) Small broomrape (Orobanche minor) germination and early 

development in response to plant species. Weed Sci. 52, 260-266. 

Rubiales D, Ferna´ Ndez-Aparicio M, Wegmann K & Joel DM (2009) Revisiting strategies for reducing the 

seedbank of Orobanche and Phelipanche spp. Weeds Research. 49, 23-33. 

SauerbornJ, Müller-Stöver D& HershenhornJ (2007) The role of biological control in managing parasitic weeds. 

Crop Prot. 26, 246-254. 

Yoneyama K, Xie X& Kusumoto D et al. (2007) Nitrogen deficiency as well as phosphorus deficiency in sorghum 

promotes the production and exudation of 5-deoxystrigol, the host recognition signal for arbuscular 

mycorrhizal fungi and root parasites. Planta 227, 125-132. 

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Biological characteristics of Iva xanthifolia (Giant sumpweed ) and its controll by soil 

herbicides 

D. Marisavljevic 1 , B. Konstantinovic 2 , D. Pavlovic 1 and M. Meseldzija 2 

1 

Institute for plant protection and environment,Teodora Drajzera 9, 11000 Belgrade (Serbia). Email: 

marisavljevicd@yahoo.com 

2 

Agricultural faculty, Novi Sad, Trg Dositeja Obradovica 8, 21 000 Novi Sad (Serbia) 

Introduction 

Iva xanthifolia Nutt. is an invasive alien weed species which has intensively 

spread over the territory of Serbia, and it has gradually moved from noncrop 

areas to crop fields. On average, a single I. xanthifolia plant can produce up to 

50 000 seeds. As a part of extensive research into its spreading, bioecological 

characteristics and possibilities of chemical control with herbicides were 

examiden in this study The study has been carried out on I. xanthifolia seeds 

and the conditions for its germination. The aim of the research was to determine 

the time and pace of I. xanthifolia growth, and therefore develop a better 

strategy against its spread. In addition, the possibilities for the chemical control 

of I. xanthifolia by using soil herbicides have been tested aiming to prevent its 

massive spread. Seed of I. xanthifolia from our areas can be categorized into 

two groups: larger seeds, which are 1-1.6 mm long, and smaller seeds, which 

are 0.75 mm long, and they stand in relation 65% (larger seed) to 31% (smaller 

seed). The germination starts at the temperature of 5 0 C, and the greatest 

germination % is at 10 0 C (45%) and the lowest % of germination is at 20 0 C 

(18%). Regarding the time for the beginning of the germination, the shortest 

period is 4 days, at 20 0 C, and the longest period which is 12 days is at 5 0 C. 

However, in the temperatures below 20 0 C seedlings are well developed, while 

at the temperature above 20 0 C a great number of deformed seedlings has been 

noticed. The most widely applied soil herbicides have been used in this 

experiment for testing the possibilities of controlling I. xanthifolia and all of the 

tested soil herbicides showed good efficiency. 

Iva xanthifolia Nutt. was recorded in Serbia for the first time in 1966 in Vojvodina, near Novi 

Sad (Šajinoviš & Koljadţinski, 1966) and later described by Mijatoviš (1973). The results of the 

research carried out from 1973 to 1977 (Šajinoviš & Koljadţinski, 1978) showed that I. 

xanthifolia could already be found in 21 places in Vojvodina. In addition to these studies, I. 

xanthifolia was mentioned as a typical plant of noncrop habitats. Until 1996, when Veljkoviš 

(1996) pointed out that this plant was spreading, there had not been any additional studies. 

Since the late 1990's the spread of I. xanthifolia has been intensified in the whole territory of 

Vojvodina, while its expansion has been noticed in certain parts of Srem. Furthermore, it already 

appeares in all row crops, even in cereals in parts of field where the number of plants is lower 

(Kojiš & Ajder, 1996). This kind of spread of I. xanthiifolia was expected because field 

observations, in addition to immense scientific studies (Marshall & Moonen, 2002; Gabriel et al., 

2005), suggest that weeds which carry lots of seeds from noncrop habitats (even with preventive 

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measures) gradually enter the crops, especially row crops. Entering the crops, the weeds adjust to 

agrofitocenoses and in spite of their plasticity, if the crop is more competitive, the number of 

weeds decreases together with the production of their seeds (Grundy et al., 2004; Debaeke, 

1988). Therefore, it happens that in row crops there is a smaller number of individually welldeveloped 

plants which are better developed than in densely populated noncrop habitats. The 

total sum of the seeds is usually smaller than the one in the areas where we can find a higher 

number of poorly developed plants (Benjamin & Aikman, 1995). From this point of view, the 

spread of weeds, I. xanthifolia being one of them, can also be observed through the quantity of 

seeds in the soil. However, there is no correlation between the quantity of weed seeds in the seed 

bank and the germination of seeds in the crops as demonstrated by Rahman et al. (2004). These 

authors have studied the weed seed-bank in a maize and discovered an average weed seed 

germination of 2.1-8.2 % of all present species. Nevertheless, the relationship between the 

quantity of seeds of certain species, which are present in the soil, and their germination cannot be 

established, especially for species whos seeds are the most frequent. This fact makes the weed 

control more difficult, especially when it comes to newly introduced and poorly studied species 

like I. xanthifolia. 

In order to prevent massive spread of I. xanthifolia in Serbia, when this species appeared in the 

crops, preliminary studies of the possibility of controlling this weed in sugar beet, soybean, 

sunflower and maize crops were carried out (Marisavljeviš & Veljkoviš, 2000, 2002). These 

studies show the difficulties in finding the optimum solutions for controlling I. xanthiifolia. With 

the aim of preventing the damage to the plant production I. xanthifolia is included in the A2 List 

of quarantine damaging organisms found on the territory of the ex Federal Republic of 

Yugoslavia, and due to its spread, I. xanthifolia has become an invasive species in Serbia 

(Vrbniţanin et al., 2004). 

The aim of the research was to determine the time and pace of I. xanthifolia growth, and 

therefore develop a better strategy against its spread. In addition, the possibilities for the chemical 

control of I. xanthifolia by using soil herbicides have been tested aiming to prevent its massive 

appearance in agrofitocenose. 

Material and methods 

Germination tests of I. xanthiifolia seeds 

I. xanthifolia (Asteraceae) – false ragweed or giant sump weed - is an annual, termophyl 

native to Canadia (Scoggan, 1978). Seeds of I. xanthifolia were collected from different sites at 

Nova Pazova in 2004 and 2005. The study was carried out in 2006 together with the tests of 

germination faculty. Seed size, quantitative ratio of seed sizes and weight of 1000 seeds were 

measured. Twenty seeds were placed in Petry dishes (9 cm in diameter) with filter paper 

(following Miloševiš & Široviš, 1994). The moisture content of the filter paper was kept constant 

by adding water. The seeds germinated from July to December 2006. The first measurement of 

seed germination (―seed energy―) was performed when the first normally developed seedlings 

appeared, while the final measurement (―full germination―) was carried out when there were no 

more new seedlings (and when the base was infected by microorganisms to such extent that the 

germination could no longer be observed). The length of the study of seed germination was 

influenced by the temperature as well. In preliminary studies, the seeds were disinfected using the 

2 % mixture of fungicides, but it was noticed that the full germination was decreased compared to 

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410

the control seeds, so this treatment was omitted in latter stages of the study. Seeds germinated in 

a growth chamber at the temperature of 5, 10, 15, 20 and 25 0 C. Each treatment was repeated five 

times. The optimal temperature for germination was also determined according to the biggest 

number of germinated seeds, and the characteristics of hypocotyls and epicotyls of germinated 

seeds were visually assessed. 

Impact of herbicides on the germination of I. xanthiifolia seeds 

Seeds of I. xanthifolia were used for the biotest in March 2005. The seeds were prepared by 

holding them between two pieces of damp filter paper inside Petry dishes, in order to accelerate 

swelling. After that, the seeds with the broken seed coat were moved to Petry dishes (9 cm 

diameter) on the filter paper. The applied herbicides are the most commonly used soil herbicides 

in Serbia: 

1. Prometrin 500 (prometryn, 500 g a.m. L -1 ): 1.27; 0.95; 0.63; 0.47; 0.32 mg/5 ml or 2.00; 1.50; 

1.00 and 0.50 L ha -1 , 

2. Trifluralin 48 EC (trifluralin, 480 g a.m./L): 1.20; 0.60; 0.30 and 0.15 mg/5 ml or 2.00; 1.00; 

0.50 and 0.25 L ha -1 

3. Frontier 900 EC (dimethenamid, 900 g a.m. L -1 ): 1.36; 1.13; 0.90; 0.68 mg/5 ml or 1.20; 1.00; 

0.80 and 0.60 L ha -1 , 

4. Guardian (acetochlor, 840 g a.m. L -1 ): 2.48; 2.04; 1.69; 1.01 mg/5 ml or 2.20; 1.80; 1.50 and 

0.90 L ha -1 , 

5. Dual Gold 960 EC (s-metolachlor, 960 g a.m. L -1 ): 1.69; 1.20; 0.84 and 0.60 mg/5 ml or 1.40; 

1.00; 0.70 and 0.50 L ha -1 

Twenty seeds were put in each Petry dish, and 5 ml of herbicide mixture at different 

concentrations (described above) were added, plus untreated control. Mixtures were created by 

adjusting the quantities of herbicides applied to the size of the Petry dish. The quantity of liquid 

was chosen to suit the filter paper and retain moisture at the beginning of the experiment. During 

the experiment, moisture of filter paper in Petry dishes was controlled by adding water. Each 

variant was repeated five times. The condition of seedlings was followed daily, and a visual 

assessment of the condition (vitality) of seedlings and measurements of the length of radicles 

were performed every three days. The experiment lasted 14 days, until the radicles of the seed 

from the control variant started decomposing. 


Statistical analysis was performed with the SigmaPlot 4.0 software (1997). The experimental 

results of germination studies were examined visually. Values on the germination of seeds under 

the influence of tested herbicides were analysed using LSD test (multiple comparsion statistical 

test) . 


By testing the characteristics of I. xanthifolia seeds, the following results were obtained: 

The average length of the seed is 0.75 (min) -1.80 (max) mm and on the basis of these 

values 2 basic seed groups were defined: seed >1 mm and seed

Seeds germination. Tests of the germination of I. xanthifolia seeds (Table 1) showed that the 

seed begins to germinate at 5þC. The major percentage of germinated seeds was obtained at 10 

þC (45%), and the smallest percent at 20 þC (18%). The higher percentage of germinated seeds 

was observed with seed group > 1mm. With rises in temperature from 5 þC to 10 þC and 15 þC, 

the seed germinates faster and maintains that tendency until the temperature reaches 20 þC. With 

further rises in temperature, the germination slows down, so that it takes 11 days for the seed to 

germinate at 25 þC (Table 1). Concerning the time necessary for the beginning of germination of 

I. xanthifolia seeds, the shortest period was observed at 20 þC (4 days), and the longest at 5 þC 

(12 days). These results are in accordance with the data on the speed of I. xanthifolia germination 

by Milanova (2001). At temperatures below 20 þC the seed germinated slower, but the seedlings 

were well-developed, while at the temperature of 20 þC a higher number of deformed I. 

xanthifolia seedlings was discovered. 

Table 1 - Average I. xanthifolia germination at different temperature and time duration 

Seed size 

Temperature 

5 0 C 10 0 C 15 0 C 20 0 C 25 0 C 

< 1.00 mm 25 % 39 % 21 % 14 % 12% 

> 1.00 mm 22 % 45 % 24 % 18 % 16% 

Time duration (days) 12 10 6 4 11 

The impact of herbicides on the germination of I. xanthifolia 

All tested soil herbicides were efficient in preventing the germination of I. xanthifolia seeds. 

During the experiment in four tests the growth of seedlings (length of radicle) was observed. In 

the first assessment, three days after the start of the test, the seeds from all variants have started 

germinating, but the growth of the radicle of the treated seeds decelerated after three days only 

i.e. the radicles started to rot. Fourteen days after the beginning of the germination, radicles were 

completely rotted in all variants of tested herbicides. The values of Iva xanthifolia Nutt seed 

germination under the influence of tested herbicides are showed in Tables 2-6. 

Table 2 - Germination of I. xanthifolia seeds treated with Trifluralin 48 EC 

Relation of treatments 

Marks 

I II III IV 

K : 2.00 Lha -1 ** ** ** ** 

K : 1.00 Lha -1 ** ** ** ** 

K : 0.50 Lha -1 ** ** ** ** 

K : 0.25 Lha -1 ** ** ** ** 

2.00 : 1.00 Lha -1 ns ns ns ns 

2.00 : 0.50 Lha -1 ns ns ns ns 

2.00 : 0.25 Lha -1 ns ns ns ns 

1.00 : 0.50 Lha -1 ns ns ns ns 

1.00 : 0.25 Lha -1 ns ns ns ns 

0.50 : 0.25 Lha -1 ns ns ns ns 

p < 0.01 ** ; ns no significant differences 

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412

Table 3 - Germination of I. xanthifolia seeds treated with Dual Gold 960 EC 

Relation of treatments Marks 

I II III IV 

K : 1.40 Lha -1 ** ** ** ** 

K : 1.00 Lha -1 ** ** ** ** 

K : 0.70 Lha -1 ** ** ** ** 

K : 0.50 Lha -1 ** ** ** ** 

1.40 : 1.00 Lha -1 ns ns ns ns 

1.40 : 0.70 Lha -1 ns ns ns ns 

1.40 : 0.50 Lha -1 ns ns ns ns 

1.00 : 0.70 Lha -1 ns ns ns ns 

1.00 : 0.50 Lha -1 ns ns ns ns 

0.70 : 0.50 Lha -1 ns ns ns ns 

p < 0.01 ** ; ns no significant differences 

Table 4 - Germination of I. xanthifolia seeds treated with Frontier 900 EC 


I II III IV 

K : 1.20 Lha -1 ** ** ** ** 

K : 1.00 Lha -1 ** ** ** ** 

K : 0.80 Lha -1 ** ** ** ** 

K : 0.60 Lha -1 ** ** ** ** 

1.20 : 1.0 Lha -1 ns ns ns ns 

1.20 : 0.80 Lha -1 * ns ns ns 

1.20 : 0.60 Lha -1 ns ns ns ns 

1.00 : 0.80 Lha -1 ns ns ns ns 

1.00 : 0.60 Lha -1 ns ns ns ns 

0.80 : 0.60 Lha -1 ns ns ns ns 

p < 0.01 ** ; P < 0.05 *; ns no significant differences 

Table 5 - Germination of I. xanthifolia seeds treated with Prometrin 500 


I II III IV 

K : 2.00 Lha -1 ** ** ** ** 

K : 1.50 Lha -1 ** ** ** ** 

K : 1.00 Lha -1 ** ** ** ** 

K : 0.50 Lha -1 ** ** ** ** 

2.00 : 1.50 Lha -1 * ns ns ns 

2.00 : 1.00 Lha -1 ns ns ns ns 

2.00 : 0.50 Lha -1 ** ns ns ns 

1.50 : 1.00 Lha -1 ns ns ns ns 

1.50 : 0.50 Lha -1 ns ns ns ns 

1.00 : 0.50 Lha -1 * ns ns ns 

p< 0.01 **; P < 0.05 *; ns no significant differences 

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413

Table 6 - Germination of I. xanthifolia seeds treated with Guardian 


I II III IV 

K : 2.20 Lha -1 ** ** ** ** 

K : 1.80 Lha -1 ** ** ** ** 

K : 1.50 Lha -1 ** ** ** ** 

K : 0.90 Lha -1 ** ** ** ** 

2.20 : 1.80 Lha -1 ns ns ns ns 

2.20 : 1.50 Lha -1 ns ns ns ns 

2.20 : 0.90 Lha -1 ns ns ns ns 

1.80 : 1.50 Lha -1 ns ns ns ns 

1.80 : 1.50 Lha -1 ns ns ns ns 

1.50 0.90 Lha -1 ns ns ns ns 

p < 0.01 **; ns no significant differences 

After the analysis of the obtained data the following conclusions were drawn: 

there are statistically significant differences between control (without herbicide) and each 

herbicide concentration on germination of I. xanthifolia seeds 

there were no statistically significant differences between tested concentrations of each 

tested herbicide rate. 

Conclusions 

The results of the study on I. xanthifolia seed characteristics show that the conditions of our 

habitats fit this invasive species. This corresponds with the findings regarding the two main seed 

groups ced: major portion is represented by larger seeds. Larger seeds show better germination 

ability, and the temperatures which suit this plant for optimum germination are also present in our 

country during the spring season (from 5 to 20 0 C). The tests of the performance of soil 

herbicides on I. xanthifolia Nutt germination suggest that this plant is very sensitive to soil 

herbicides, which means that application of tested soil herbicides can be an effective way of 

controlling it. Moreover, the results suggest that besides standard reccomended quantities of these 

herbicides, with the aim of decreasing the application of soil herbicides, I. xanthifolia can also be 

controlled with half the amount of above tested soil herbicides. 

References 

Kojiš M & Ajer S (1996) [Problems of biodiversity in agrarian ecosystems] Problemi biodiverziteta u agrarnim 

ekosistemima, Proceedings of the 5th Weed Symposium, Banja Koviljaca, 35-63. 

Marshall E & Moonen A (2002) Field margins in northern Europe: their functions and interactions with agriculture. 

Agriculture, Ecosystems & Environment 1-2, 5-21. 

Gabriel D, Thies C & Tscharntke T (2005) Local diversity of arable weeds increases with landscape complexity. 

Perspectives in Plant Ecology, Evolution and Systematics 7, 85-93. 

Grundy A, Mead A & Burstons S (2004) Seed production of Chenopodium album L. in competition with field 

vegetable. Weed Research 44, 271-281. 

Deebaeke P (1988) Population dynamics of some broad-leaved weeds in cereals II. Survival Luecke and seed 

production. Weed Research 28, 265-279. 

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414

Benjamin L & Aikman D (1995) Predicting growth in stands of mixed species from that in individual species. Annals 

of Botany 76, 31-42. 

Marisavljeviš D & Veljkoviš B (2000) [Iva xantaifolia Nutt.- new weed in our fields and the possibility of chemical 

control] Iva xantaifolia Nutt. – novi korov na našim poljima i mogušnost hemijskog naţina suzbijanja.. 

Proceedings of the 11th Yugoslav Symposium on Plant Protection with international character, Zlatibor, 109. 

Marisavljeviš D & Veljkoviš B (2002) Iva xanthifolia Nutt.: A problematical weed in sugar beet in Yugoslavia. 

Proceedings of the 12th Symposium European Weed Research Society, Wageningen, The Netherlands, 210- 

211. 

Rahman A, James T, Mellsop, JM & Grbavac N (2004) Predicting broadleaf weed populations in maize from the soil 

seedbank. Proceedings of a conference, Hamilton, New Zealand, 281-285. 

Scoggan HJ (1978) The flora of Canada. Natural Museum Nat.Сci. (Ottawa) Publ.Bot. 7(1) - 7(4). 1711. 

Šajinoviš B & Koljadţinski B (1966) [New adventive species Iva xanthifolia Nutt. (Cychachaena xanthifolia Fresen) 

in our country] Nova adventivna vrsta Iva xanthifolia Nutt. (Cychachaena xanthifolia Fresen) u našoj zemlji. 

Pamphlet of Natural History Museum, Belgrade, Ser. B 21, 217-220. 

Šajinoviš B & Koljadţinski B (1978) [Addition to the studies of the process of naturalisation of adventive plant 

species- Ambrosia artemisiifolia L. 1753. and Iva xanthifolia Nutt. 1818. (Asteraceae) in Vojvodina] Prilog 

prouţavanju procesa naturalizacije adventivnih biljnih vrsta - Ambrosia artemisiifolia L. 1753. i Iva 

xanthifolia Nutt. 1818. (Asteraceae) u Vojvodini. Biosistematika 14, 81-92. 

Veljkoviš B (1996) [Distribution of newly introduced weed species Ambrosia arthemisiifolia L. and Iva xanthifolia 

Nutt. in Yugoslavia] Rasprostranjenost novounešenih korovskih vrsta Ambrosia arthemisiifolia L. i Iva 

xanthifolia Nutt. u Jugoslaviji. Procedings of the 5th Weed Symposium, Banja Koviljaca, 351-363. 

Vrbniţanin S, Karadţiš B & Dajiš-Stevanoviš Z (2004) [Adventive and invasive weed species on the territory of 

Serbia] Adventivne i invazivne korovske vrste na podruţiju Srbije. Acta herbologica 13, 1-13. 

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415

Allelopathic potential of rice (Oryza sativa) cultivars of barnyard grass (Echinochloa crusgalli) 

Leila Jafari 1 , Hossein Ghadiri 2 and Ali Moradshahi 3 

1- Former MS Student of Department of Agronomy, College of Agriculture, Shiraz University, 

and current faculty member of Hormozgan University, Iran. E-Mail address: leilajaf@yahoo.com 

2- Professor of Department of Agronomy, College of Agriculture, Shiraz University, Iran. 

3- Associated professor of Department of Biology, College of Science, Shiraz University, Iran. 

Introduction 

Laboratory and greenhouse studies were conducted to assess the allelopathic 

potential of 12 rice cultivars on barnyard grass. Polyethylene glycol (PEG) was 

used to determine the influence of osmotic potential on the bioassay materials. 

Effect of different concentrations (5, 10, 20, 30, 40, and 60%) of stem, root, and 

leaf aqueous extracts of rice cultivars on seed germination, radicle and primary 

shoot length of barnyard grass seedlings, and rate of respiration of root pieces 

were investigated in the laboratory experiments. Shoot height and dry weight of 

weed stands were studied in the greenhouse. Also total peroxidase activity, 

chlorophyll pigment and mitotic index were determined. Results indicated that, 

among rice cultivars, Mehr, Tarom-mahali, G3, Nemat, and Shahpasand caused 

the most inhibition effects on investigated factors. Amol-3 showed the least 

negative effects on growth of seedlings and stands of barnyard grass. In 

laboratory, the Mehr cultivar demonstrated the maximum inhibitory effects by 

reducing barnyard grass seed germination percentage (88%), radicle length 

(100%), primary shoot length (83%), and root respiration (85%) Cell division, 

expressed as mitotic index, was significantly reduced in the presence of rice 

aqueous extracts. Mehr cultivar had higher inhibitory effect on mitosis 

compared to Amol-3 and leaf extract in both species. In greenhouse, the same 

cultivar showed the maximum inhibitory effect by reducing barnyard grass 

height (45%) and dry weight (64%). With increase in extract concentration, the 

inhibitory effect increased. Leaf extract from rice plants was more effective 

compared with the root and stem extracts. These results suggest that rice leaf 

extracts may be a source of natural herbicide. 

Rice (Oryza sativa L.) is the most important cereal crop in the developing world and is the 

staple food of over half the world‘s population (Juliono,1993). Increasing population pressures in 

rice- consuming nations require more attention toward novel approaches to increasing 

production. Yield increases must be achieved through agronomic approaches that are 

environmentally safe. Controlling weeds though sustainable methods, is a focal point for 

researchers working to ensure the world food supply for future generations (Olofsdotter et al., 

1999). 

Weeds are the most severe and the most widespread biological constraint to rice production 

(Zimdahl, 1999; Rao, 2000). They are the constant component of agroecosystems unlike insect 

pests and plant diseases that attack periodically (Raju, 2000). Barnyard grass (Echinochloa crus- 

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416

galli L.) is the most troublesome weed in both tropical and temperate regions of the world. This 

weed is very competitive in rice and can reduce yields to zero (Rice, 1984; Maun and Barrett, 

1986). To cope with increasing weed problems, herbicide use is increasing rapidly all over Asia. 

Concerns about human health and environmental pollution, in addition concerns about the 

development of herbicide- resistant weeds, make the development of weed management methods 

with a minimal use of chemicals an area of interest. . One option to reduce herbicide dependency 

would be to use the allelopathic potential of a species (Olofsdotter et al., 1999). Rice (1984) 

defined allelopathy as any direct or indirect harmful or beneficial effect by one plant (including 

microorganisms) on another through the production of chemical compounds that escape into the 

environment. Allelopathic compounds are released into the environment through leaching or 

emission from living plant parts, root exudation, volatilization, and residue decomposition 

(Inderjit, 1996; Putnam and Tang 1986). 

Considerable attention has been paid on the positive aspects of allelopathy as an ecological 

control by selecting rice cultivars with greater allelopathic potentials (Chung et al., 2001; Dilday 

et al., 1998; Hassan et al., 1998; Lin et al., 1992; Mousavi, 2000; Olofsdotter, 1997; Jung et al., 

2004). Bioassay was conducted to examine the allelopathic effects of different parts of rice 

plants, and the genetic and phenotypic characters of rice varieties, on barnyard grass (Jung et al., 

2004). Several accessions of rice germplasm in the field were found to decrease the growth of 

ducksalad Heteranthra limosa (Sw.) Willd, an annual broadleaf weed (Dilday et al., 1998). At 

IRRI, laboratory screening and field experiments have shown that 19 of 111 rice cultivars tested 

were able to suppress the growth (dry matter) of barnyard grass by more than 40%. Suppression 

in the field was comparable with root reduction observed in laboratory screening (Navarez and 

Olofsdotter,1996; Olofsdotter and Navarez, 1996). The rice accessions with allelopathic potential 

originated from 37 countries indicating that allelopathy is widespread in rice germplasm. One 

thousand rice accessions have been screened for allelopathic potential against barnyard grass and 

variable flatsedge (Cyperus difformis) in field experiment in Egypt. Of these 30 accessions 

showed promising allelopathic potential (50-90%weed reduction) against barnyard grass and 15 

were allelopathic (30- 75% weed reduction) against flatsedge. Five cultivars showed strong 

allelopathic potential for both weed species (Hassan et al., 1998). Chung et al. (2001) evaluated 

47 domestic rice cultivar extracts for allelopathic potential against barnyard grass. Also, they 

reported that there may be genetic differences among rice cultivars for allelopathic potential on 

barnyard grass using 44 cultivars hull extracts. In a study, Dali et al (2000) evaluated the 

allelopathic effect of rice varieties on weeds. Results showed the inhibitory effect of rice on the 

root growth of barnyard grass was higher than the effect on shoot growth. The putative 

compound causing the inhibitory effect of rice was isolated from rice root exudates, and the 

chemical structure of the inhibitor was determined by spectral data as 3,20-epoxy-3α-hydroxy- 

9β-pimara-7,15-dien-19,6β-olide (momilactone B) and 3β-Hydroxy-9β-pimara-7,15-diene-19,6βolide 

(momilactone A) (Kato-Nouguchi et al., 2008; Kato-Noguchi and Ino, 2005; Kato-Noguchi, 

2004). Also flavone (5,7,4′-trihydroxy-3′,5′-dimethoxyflavone), cyclohexenone (3-isopropyl-5acetoxycyclohexene-2-one-1) 

and a liquid mixture of low polarity, containing long-chain and 

cyclic hydrocarbons, were isolated from leaves of allelopathic rice accession PI 312777 using 

column chromatography (Kong et al., 2004). Bioassays showed that both the flavone and 

cyclohexenone significantly inhibited the growth of weeds barnyard grass, flatsedge and ricefield 

flatsedge (Cyperus iris) (Kong et al., 2004). On the other hands, Kong et al. (2008) showed that 

allelopathic rice can have great impact on the population and community structure of soil 

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417

microbes (Kong et al., 2008). The aim of this study was to identify and screen Iranian rice 

cultivars for possible allelopathic activity against barnyard grass. 


Plant materials 

Based on a preliminary experiment (data not shown), twelve rice cultivars out of twenty-one 

were selected from different areas in Iran, eleven of which had potential allelopathic effect 

(Mehr, Champa, Tarom -mahali, Fajr, Nemat, Anbori -siyah, Shahpasand, G3, G8, 1658- 4- 26- 

1- 1 and 1658- 5- 3- 1- 1), and one (Amol – 3) did not show any potential allelopathic effect. 

Mature seeds of barnyard grass were scarified with a rotating scarifier which rubs the seeds 

together and against an abrasive surface. 

Extraction 

Rice stems, roots, and leaves were sampled at the three-to four-leaf stage of plants that were 

grown in the greenhouse. Fresh plant samples were stored at –20 C. One hundred milliliters of 

distilled water were added to 10 grams of fresh leaf, stem or root and crushed (Ebana et al., 

2001). Each sample was stirred on a rotary shaker for 24 h and centrifuged at 3000 rpm for 

15min. This extract, considered as full strength (100%), was recovered and stored in a 

refrigerator until it was used as a crude water-soluble extract. Aliquots of the extract were taken 

and diluted to 75, 60, 50, 40, 30, 25, 20, 15, 10 and 5% strength with distilled water. 

Bioassay in the laboratory 

Osmotic potential was measured by Cryoscopy method (Moustafa et al., 1996). The osmotic 

potential of each cultivars stem, root, and leaf extract was almost similar. Polyethylene glycol, 

PEG an inert, nonionic, long-chain polymer: HOCH2- (CH2-O-CH2) X CH2 OH (carbowax 

6000) has been widely used in experimental media at predetermined water potential values 

(Steuter et al., 1981). Under the same conditions, experiments with extracts of leaf, root, and 

stem of rice cultivars and PEG experiment were concurrently conducted to distinguish between 

the inhibitory effects of substances and osmotic potential of extract concentrations. The same 

measurements were performed using PEG instead of different extracts. Thirty barnyard grass 

seeds were placed on two Whatman No.2 filter papers in 9-cm petridishes. Seven milliliters of the 

appropriate extract in 5, 10, 20, 40, and 60% concentrations and distilled water as the control 

were applied to the seeds. PEG was used on the bioassay materials to determine the influence of 

osmotic potential. Petridishes were incubated at 25C in the dark for 5d. The number of 

germinated seeds was recorded and the length of radicles, primary shoots and root respiration rate 

of 6 d old seedlings were measured and averaged for each replicate with each treatment. A 

factorial experiment based on completely randomized design with three replications was used. 

Bioassay in the greenhouse 

A greenhouse experiment was conducted to evaluate the effect of stem, root, and leaf extract 

of rice plants on the height and dry weight of barnyard grass. At the three-leaf stage of barnyard 

grass, pots were irrigated with 250 ml of the appropriate extract (25, 50 and 75%) or with 

distilled water (control treatment). Ten days after the addition of extracts to pots, barnyard grass 

seedlings were harvested and their heights (from the basal node to the end of leaf) measured. 

Then, plants were dried in the oven at 70˚C for 48 h and their dry weights recorded. A factorial 

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418

experiment based on completely randomized design with three replications was used. Data were 

analyzed by the analysis of variance procedure, and the means were separated using Duncan‘s 

new multiple range test at the, α = 0.05 level of significance (SAS, 2000). All experiments 

replicated twice. Based on laboratory and greenhouse experiments results, two rice cultivars 

(Amol-3 and Mehr) were selected to determine total peroxidase activity, chlorophyll content and 

mitotic index. 

Preparation of aqueous leaf and root extracts 

Aqueous leaf and root extracts of two rice cultivars were prepared by homogenizing 10 g of 

fresh tissues in 100 ml deionized water. The homogenates were stirred for 2 h on magnetic stirrer 

at room temperature and then centrifuged at 5000 g for 20 min. The supernatants were diluted 

with deionized water to give required concentrations. 

Extraction and determination of total peroxidase activity 

Seeds of barnyard grass were soaked in 1% sodium hypochlorite for 15 min and then 

thoroughly rinsed with deionized water. The seeds were germinated in plastic containers at room 

temperature. After seven days, uniform size seedlings were transferred to plastic pods containing 

1 L half strength Hoagland solution and kept in a growth room set at about 24º c and 16 h 

photoperiod. After two days, seedlings were treated with proper concentrations of extracts for 

three days and total peroxidase was extracted from the roots of 12 d old barnyard grass seedlings 

and assayed according to Mac-Adam et al (1992). Changes in absorbance at 430 nm were 

recorded at 10 sec intervals and the slopes of the lines were calculated and enzyme activity was 

expressed as percentage of the control. 

Chlorophyll extraction and measurement 

Seedlings grown in plastic containers and treated with different concentrations of rice extracts 

as above were used for chlorophyll determination. Fully expanded leaves were taken randomly 

from the seedlings and their fresh weights were determined. Chlorophyll pigments were extracted 

and measured according to Arnon (1949). 

Determination of mitotic index 

Onion (Allium cepa L.) bulbs rooted in water in the laboratory were used to measure the 

effects of rice shoots and roots extracts on cell division. The rooted onions were placed on top of 

100 ml beakers with roots immersed in different concentrations of rice leaf or root aqueous 

extracts. After 24 h, root tips, 5 mm in length, were cut and stained with Schiff‘s reagent (Ruzin, 

1999) and used to determine mitotic index (Moradshahi et al., 2002). The design for each of the 

laboratory experiment was completely randomized design with three replications. All 

experiments were replicated twice. 


Allelopathic potential of rice cultivars in laboratory bioassay 

Significant differences were observed among rice cultivars in extract concentrations of 5, 10, 

20, 40, and 60% (data not shown). Maximum seed germination was obtained in the presence of 

5% concentration of Amol-3 (89%) and minimum seed germination (15%) resulted when 60% 

concentration of Mehr was used. In all extract concentrations, Amol-3 cultivar and PEG caused 

relatively similar reduction in barnyard grass seed germination. PEG concentration of 20% 

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419

significantly reduced seed germination of barnyard grass as compared to the lower PEG 

concentrations. The inhibition in barnyard grass seed germination increased with an increase in 

the concentration of rice extract. Chung et al (2001) reported that barnyard grass seed 

germination percentage was significantly inhibited as the extract concentration increased. 

Further investigations on interactions between rice cultivars and stem, root, and leaf extracts 

showed that maximum barnyard grass seed germination resulted from the application of Amol-3 

cultivar stem extract (77%) and the minimum seed germination resulted from leaf extract of Mehr 

cultivar (51%) (Table 1). Amol-3 cultivar was significantly different from the others. In this 

study, the inhibition of barnyard grass germination using different parts of rice reflects the 

allelopathic potential of individual rice varieties. Results are in agreement with Chung et al. 

(2003) and Jung et al. (2004) who reported inhibition of barnyard grass seed germination by 

allelopathic effects of rice cultivars. Jung et al. (2004) indicated that, the inhibitory effect on 

barnyard grass emergence induced by a leaves-plus-straw mixture was extremely high for the 

Damagung strain (95.9%). 

Table 1 - Effects of different parts extracts of rice cultivars on seed germination and radicle 

length of barnyard grass. † 

Rice extract 

Rice cultivar Barnyard grass seed Barnyard grass radicle length(cm) 

germination (%) 

Stem Root Leaf Mean Stem Root Leaf Mean 

Amol-3 77Aa 76Aa 75Aa 76A 1.88Aa 1.32Ab 1.33Aa 1.52A 

1658-5-3-1-1 64Bca 61Ba 63Ba 63B 1.86Aa 0.86B-Eb 0.86Bb 1.15B 

1658-4-26-1-1 64Bca 56Cb 62BCa 60BC 1.70Ba 0.87BCDb 0.83Bc 1.13B 

G8 65Bca 66Cb 60BCc 62B 0.92Ca 0.88BCDb 0.83Bc 0.88C 

Anbori-siyah 64Bca 60Cb 60BCa 62B 0.92Ca 0.91Ba 0.84Bb 0.89C 

Champa 65Bca 58Cb 59CD 

b 

62B 0.92Ca 0.89BCa 0.84Bb 0.88C 

Fajr 66Ba 59Cb 55DEc 61BC 0.84Da 0.84CDEa 0.67Cb 0.78D 

Nemat 65Bca 60Cb 58CD 

b 

61B 0.83Da 0.83DEa 0.66CDb 0.77D 

G3 66Ba 60Cb 59CD 61B 0.83Da 0.84BCDE 0.64CDEb 0.77D 

b 

a 

Tarommahali 

63Bca 62Ca 54EFb 59BC 0.83Da 0.83Dea 0.63CDEb 0.76D 

Shahpasand 63Bca 63Ca 54DEb 61BC 0.83Da 0.81Ea 0.61DEb 0.75D 

Mehr 62Ca 56Cb 51Fc 56C 0.83Da 0.81Ea 0.60Eb 0.75D 

PEG 77Aa 76Aa 75Aa 76A 1.89Aa 1.33Ab 1.34Ab 1.53A 

† Means within each row followed by the same letters (small letters) are not significantly 

different (Duncan 5%). 

† Means within each column followed by the same letters (capital letters) are not significantly 


Effects of rice cultivars and rice stem, root, and leaf extracts indicated that the lowest 

inhibitory effect on barnyard grass radicle length was established by stem extract of Amol-3 and 

1658- 5- 3- 1- 1 cultivars and the highest by leaf extract of Mehr cultivar (Table 1). Kong et al. 

(2004) showed that both the flavone and cyclohexenone were isolated from leaves of allelopathic 

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420

ice significantly inhibited the growth of weeds barnyard grass, flatsedge and ricefield flatsedge 

(Cyperus iris). Maximum radicle length (1.52 cm) resulted from the application of Amol-3 

cultivar and minimum radicle lengths (7.5-7.8 mm) resulted from the application of Mehr, 

Shahpasand, Tarom-mahali, G3, Nemat and Fajr cultivars extract. These cultivars showed 

significant differences from other cultivars and PEG. Our results indicated that leaf extracts have 

less inhibitory effect on primary shoot length (data not shown) when compared with radicle 

length. 

Interaction effects of rice cultivars and extract concentrations on radicle length showed that 

the minimum negative effect on radicle length was related to the application of G8 rice cultivar 

extract concentration of 5% (2.64 cm) (Table 2). Maximum negative effect on radicle length was 

caused from using Mehr, Shahpasand, Tarom-mahali, G3, Champa, Nemat, and Anbori-siyah rice 

cultivar extract concentration at 60%. In 60% extract concentration, all cultivars with the 

exception of Amol-3 reduced barnyard grass radicle length about 100%. This value clearly shows 

the inhibitory effect on barnyard grass seedling growth. Radicle length of barnyard grass seeds 

was unaffected by PEG concentrations of 5 and 10%. This indicates that any reduction in 

barnyard grass seed radicle length using 5 and 10% extract concentrations of different rice 

cultivars must have been the result of allelochemicals in the extracts. 

Rice cultivars and extract concentration interactions indicated that, in the presence of 5% 

concentration, Amol-3, resulted the lowest inhibitory effect on primary shoot length (Table 2). 

The application of Mehr and Tarom-mahali at 60% concentration had the most, inhibitory effect 

on primary shoot length (83.45%). With 5% concentration, except for Amol-3 cultivar, no 

significant differences existed between cultivars. All rice cultivars at all concentration showed 

significant differences as compared to Amol-3 cultivar and PEG. Primary shoot length of 

barnyard grass seeds was affected by different PEG concentrations. In all cultivars, significant 

differences were observed between PEG and all cultivars expecte Amol-3. This different 

influence of extracts and PEG concentrations suggests that the reduction in seed germination and 

seedling growth is the result of allelochemicals in the extracts. Some allelochemicals in rice 

extracts were known by authors, and the most important of these compounds, are mamilactons 

(Kato-Noguchi and Ino, 2005; Kato-Noguchi, 2004; Kato-Nouguchi et al., 2008). The similarity 

between the influences of Amol-3 extract and PEG concentrations shows that the effect of this 

cultivar was osmotic. This suggests that any reduction in barnyard grass seed primary shoot 

length using extract ar different concentrations of rice cultivars may have been the result of either 

the osmotic potential of the extracts or allelochemicals in the extracts. Barnyard grass radicle 

growth was quite sensitive to rice extracts. These findings are in agreement with Ebana et al. 

(2001) who indicated that the stem and root extracts were less effective in comparison with the 

leaf extract. Lin et al. (2000) indicated that the inhibition in weed growth increased with an 

increase in the concentration of rice extract, and radicle length was more sensitive to aqueous 

extract than hypocotyls length. Pheng et al. (1999) reported that, under laboratory conditions, 11 

rice cultivars provided 58-78% and 32-58% root and shoot reductions respectively. These results 

confirm the results reported by Dali (2000), Olofsdotter and Navarez (1996), and Kim and Shin 

(1998) that the inhibitory effect of rice on the radicle growth of barnyard grass is higher than the 

effect on shoot growth. In a similar study, Olofsdotter and Navarez (1996) observed that, root 

growth of barnyard grass was significantly inhibited by some rice cultivars, while there was no 

significant effect on barnyard grass shoot length among the tested rice cultivars. The results of 

their study showed that the root extracts of rice were less effective than leaf extracts. In constrast 

to these finding, the oat allelopathic effects against Brassica kaber of several accessions appeared 

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421

Table2 - Effects of different concentrations of rice cultivars on radicle length and primary shoot length of barnyard grass. † 

Rice 

Cultivar 

Rice extract Concentration (%) 

Barnyyard grass radicle length (cm) Barnyardgrass primary shoot length (cm) 

0 5 10 20 40 60 

Amol-3 2.62Aba 2.63Aa 1.42Ab 1.05 Ac 0.82Ad 0.61Ae 

G8 2.63Aba 2.64Aa 0.84Bb 0.62Bc 0.11Bd 0.06Be 

1658-4-26-l-l 2.61ABCa 2.63Aa 0.84Bb 0.62Bc 0.08BCDe 0.02Be 

1658-5-3-1-1 2.61ABCa 1.16Bb 0.85Bc 0.60Bd 0.08BCDe 0.01Be 

Fajr 2.63Aba 1.14Bb 0.87Bc 0.61Bd 0.09BCe 0.02Be 

Anbori- 

siyah 

2.60ABCa 1.15Bb 0.86Bc 0.62Bd 0.06BCDe 0.00Be 

Nemat 2.60ABCa 0.88Cb 0.74Cc 0.48Cd 0.03CDe 0.00Be 

Champa 2.58ABCa 0.87Cb 0.71Cc 0.47Cd 0.03CDe 0.00Be 

G3 2.58ABCa 0.87Cb 0.69Cc 0.47Cd 0.01De 0.00Be 

Tarom 

mahali 

2.54Ca 0.85Cb 0.68Cc 0.46Cd 0.01De 0.00Be 

Shahpasand 2.57Bca 0.86Cb 0.69Cc 0.46Cd 0.01De 0.00Be 

Mehr 2.56Bca 0.85Cb 0.67Cc 0.45Cd 0.01De 0.00Be 

PEG 2.65Aa 2.65Aa 2.64Aa 1.07Ab 0.80Ac 0.61Ad 

0 5 10 20 40 60 

6.19Aa 5.70Ab 5.47Ac 4.98Ad 3.97Ae 3.56Af 

6.08Aa 5.04Bb 5.07Bc 4.39Bd 2.53Ce 1.36Bf 

6.02Aa 4.91Bb 4.89CD 

6.02Aa 4.88Bb 4.91Cb 4.26CD 

5.97Aa 4.81Bb 4.80Db 4.15CD 

5.97Aa 4.81Bb 4.79Db 4.14DE 

5.93Aa 4.81Bb 4.83Db 4.14DE 

5.90Aa 4.81Bb 4.73DE 

5.93Aa 4.80Bb 4.70DE 

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b 

c 

c 

4.30Cc 2.61Bd 1.24Ce 

e 

c 

c 

c 

2.62Bd 1.16De 

2.40Dd 1.07Ee 

2.40Dd 1.03Efe 

2.36Ed 1.03Efe 

4.16Dd 2.41De 1.04EF 

4.03Fd 2.40De 1.03EF 

5.96Aa 4.80Bb 4.68Ec 4.14Dd 2.40De 1.02EF 

5.93Aa 4.79Bb 4.68Ec 4.10Ed 2.42De 0.98Ff 

5.92Aa 4.76Bb 4.68Ec 4.03Fd 2.38DE 

e 

f 

f 

f 

0.98Ff 

6.18Aa 5.69Ab 5.43Bc 5.01Ad 2.99Ae 3.58Af 

† Means within each row followed by the same letters (small letters) are not significantly different (Duncan 5%). 

† Means within each column followed by the same letters (capital letters) are not significantly different (Duncan 5%). 

422

to be associated with the relative amount of scopletin that was exuded from the roots (Fay and 

Duke, 1977). A weak association of the effect of the root extract with the allelopathic effect in the 

field can be explained by an immediate release after translocation from the leaves. Another 

possibility is that rice allelochemicals are not released from roots but are leached directly from 

the leaves (Ebana et al., 2001). 

Effects of rice cultivars in different extract concentrations on barnyard grass respiration rate 

showed that extract concentrations of 30 and 60% were significantly different (Table 3). 

Maximum inhibitory effect resulted from Tarom-mahali, Mehr, and Nemat at extract 

concentration of 60% (0.4, 0.5, and 0.5 μl/f.w, respectively). Patrick and Koch (1958) indicated 

that the phytotoxins inhibited the respiration, germination and growth of several different kinds 

of plants. Allelochemicals may stimulate or inhibit respiration, both of which may be harmful to 

this energy-producing process. In the case of stimulation (enhanced O2 uptake) the oxidative 

phosphorylation sequence may be uncoupled, resulting in a lack of ATP (energy) formation. 

Juglone has been shown to uncouple oxidative phosphorylation, as have a variety of aromatic 

acids, phenolics, aldehydes, flavonids, and comarin compounds (Rice, 1984). Several compounds 

isolated from soils have been shown to inhibit the respiration of plant roots. Juglone is 

particularly effective in this regard, causing more than a 90% reduction in the respiration of corn 

roots after 1h exposure (Koeppe, 1972). 

Table 3 - Effects of rice cultivars and extract concentrations on seedling root respiration rate 

(µl/hr/g.f.w) of barnyard grass.† 

Rice extracts concentration (%) 

Rice cultivar Barnyard grass seedling root respiration rate (µl/hr/g.f.w) 

0 30 60 

Amol-3 3.6Aa 3.4Aa 1.5Ab 

G8 3.6Aa 3.4Aa 1.4Ab 

1658-5-3-1-1 3.5Aa 3.4Aa 1.4Ab 

1658-4-26-1-1 3.5Aa 3.4Aa 1.4Ab 

Anbori-siyah 3.5Aa 3.3Aa 1.4Ab 

Shahpasand 3.6Aa 3.3Aa 1.4Ab 

Champa 3.5Aa 3.3Aa 1.4Ab 

Fajr 3.2Ba 3.3Aa 1.4Ab 

G3 3.2Ba 3.3Aa 0.9Bb 

Nemat 3.4Aba 2.9Bb 0.5Cc 

Mehr 3.4Aba 2.9Bb 0.5Cc 

Tarom-mahali 3.5Aa 2.9Bb 0.4Cc 





Allelopathic potential of rice cultivars in greenhouse bioassay 

Response of shoot height of barnyard grass to rice cultivars and extract concentrations indicated 

that with extract concentrations of 50% and 75%, significant differences were observed among 

rice cultivars (Table 4). The most, inhibitory effect resulted from using Mehr cultivar extract 

concentration of 75% (48.5%). 

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423

Table 4 - Effects of rice cultivars and extract concentrations on shoot height and shoot dry 

weight of barnyard grass. † 

Rice extracts concentration (%) 

Rice cultivar Barnyard grass shoot Barnyard grass shoot dry weight(g) 

height(cm) 

0 25 50 75 0 25 50 75 

Amol-3 32Aa 32Aa 32Aa 31Aa 3.52Aa 3.51Aa 3.48Aa 2.58Ab 

1658-5-3-1-1 32Aa 32Aa 31Aa 21Bb 3.52Aa 3.49Aa 2.78Bb 1.47Cc 

1658-4-26-1-1 33Aa 32Aa 30Aa 21Bb 3.52Aa 3.49Aa 2.79Bb 1.60Bc 

G8 33Aa 33Aa 29Ab 21Bc 3.52Aa 3.49Aa 2.79Bb 1.59BCc 

Fajr 33Aa 32Aa 29Ab 21Bc 3.53Aa 3.49Aa 2.79Bb 1.58BCc 

Nemat 33Aa 32Aa 29Ab 21Bc 3.52Aa 3.49Aa 2.79Bb 1.59Bc 

Champa 32Aa 32Aa 29Ab 21Bc 3.52Aa 3.19Bb 2.36Cc 1.28Dd 

Anbori-siyah 32Aa 32Aa 24Bb 18BCc 3.52Aa 3.09Cb 2.35Cc 1.61Bd 

Shahpasand 33Aa 32Aa 25Bb 18BCc 3.52Aa 3.09Cb 2.36Cc 1.61Bd 

G3 33Aa 31Aa 24Bb 18BCc 3.52Aa 3.04Db 1.96Dc 1.27Dd 

Tarom-mahali 33Aa 32Aa 25Bb 18BCc 3.52Aa 3.05Db 1.99Dc 1.29Dd 

Mehr 33Aa 32Aa 25Bb 17Cc 3.52Aa 3.08Cb 1.98Dc 1.27Dd 





Interaction effects of rice cultivars and extract concentrations on shoot dry weight of barnyard 

grass showed that in all concentrations, Mehr, Tarom-mahali, Shahpasand, G3, Anbori-siyah, and 

Nemat extracts had the most inhibitory effects which resulted in the significant reduction of shoot 

dry weight of barnyard grass as compared with other cultivars. In extract concentrations of 50 

and 75%, Amol-3 significantly showed the least inhibitory effects among cultivars. The 50% 

extract concentration of this cultivar was similar to the control. However, extract concentration of 

75% was different from the control. 

Table 5 - Effects of different parts extracts of rice cultivars on shoot height and shoot dry weight of 

barnyard grass. † 

Rice extract concentration (%) 

Rice 

extracts 

Barnyard grass shoot height(cm) Barnyard grass shoot dry weight(g) 

0 25 50 75 Mean 0 25 50 75 Mean 

Stem 33Aa 32Aa 31Aa 25Ac 30A 3.5Aa 3.5Ab 3.2Ac 1.7Ad 3.0A 

Root 33Aa 33Aa 28Bb 22Bc 29A 3.5Aa 3.3Bb 2.3Bc 1.5Bd 2.7B 

Leaf 32Aa 32Aa 24Cb 15Cc 26B 3.5Aa 3.2Cb 2.1Cc 1.4Cd 2.5C 

Mean 33Aa 32a 28b 21c 3.52a 3.21b 2.55c 1.53d 

† Means within each row followed by the same letters (small letters) are not significantly different (Duncan 5%). 

† Means within each column followed by the same letters (capital letters) are not significantly different (Duncan 

5%). 

Posters 

2 nd Effects of rice stem, root, and leaf extract and extract concentrations on shoot height of 

barnyard grass seedlings were also investigated (Table 5). The lowest height of shoot resulted 

from using 75% leaf extract concentration (15 cm). In extract concentrations of 50 and 75%, 

stem, root, and leaf extracts showed significant effects on shoot height. In extract concentrations 

424 


of 25%, stem, root, and leaf extracts showed no effects on shoot height. With increase in extract 

concentration, reduction trend continued and in extract concentrations of 75%, shoot height was 

21cm. This value indicates that the inhibitory effect on barnyard grass seedling growth is about 

37%. 

In general, extract concentrations of stem, root, and leaf caused significantly different effects 

on shoot dry weight of barnyard grass (Table 5). All extract concentrations of 25, 50, and 75% 

significantly reduced barnyard grass shoot dry weight. As compared with root and stem extracts 

(22.86 and 14.3% respectively), rice leaf extract was the most, inhibitory of barnyard grass shoot 

dry weight (28.58%). Results of greenhouse experiment showed that dry weight of barnyard grass 

seedlings was more sensitive than seedling height. As compared with root and stem extracts, rice 

leaf extract caused the maximum inhibitory effect on height and shoot dry weight of barnyard 

grass. These findings are in agreement with previous works that indicated that rice residues 

significantly suppressed the rice radicle growth; and the dry weight decreased significantly while 

increasing amounts of straw applied; however, rice coleoptile growth was not inhibited (Chou 

and Lin, 1976). In a field study, Chung et al (2001) reported that the Juma 10 cultivar has 

demonstrated the most, inhibitory effect by reducing barnyard grass dry weight (68%). Leather 

and Einhellig (1986) suggested that measuring the dry weight of the germinated seed and radicle 

may be as effective as radicle elongation. Reduction in the dry weight of weed by several 

cultivars indicated the existence of gene(s) for allelochemicals production like acetic, propionic, 

butyric, vanilic, syringic, and p-comaric acids which are known to cause reduction in plant 

growth, total biomass and act as herbicide (Young et al., 1989). 

Total peroxidase activity, chlorophyll content and mitotic index determination. 

Total peroxidase increased significantly in the presence of all rice extracts (Table 6). Leaf 

extract of Mehr cultivar had the highest stimulatory effect on peroxidase activity. At 50 g l -1 , root 

extracts of Amol-3 and Mehr cultivars increased total peroxidase by 20.1 and 32.9%, whereas 

leaf extracts caused 41.5 and 96.6% increase in enzyme activity, respectively. Changes in enzyme 

activity such as peroxidase by allelochemicals have been reported by several investigators 

(Moradshahi et al., 2003; Moradshahi et al., 2002; Baziramakenga et al., 1995). 

Lin et al (2000) indicate that, in biochemical analysis, aqueous extracts significantly blocked 

the activity of superoxide dismutase and catalase, thereby increasing free radicals, consequently 

resulting in growth reduction of banyardgrass seedling. Activities of ATPase and amylase at 

different germination times of barnyard grass were also significantly inhibited by aqueous 

extracts, but the reverse was true in proxidase and IAA oxidase. In soybean roots, low 

concentration of cinnamic acid increased peroxidase activity whereas at higher concentrations, 

peroxidase was inactivated (Baziramakenga, et al., 1995). Since some peroxidases are involved 

in cell wall tightenning process, it is possible that observed growth reduction in barnyard grass by 

rice extracts is partly due to increase in cross-linkage between cell wall polymers catalyzed by 

peroxidases. 

Leaf and root extracts from both Amol-3 and Mehr cultivars reduced chlorophyll contents of 

barnyard grass leaves. Mehr cultivars had higher effect compared to Amol-3 (Table 7). Decrease 

in chlorophyll content in the presence of allelochemicals has been reported by other investigators 

(Baziramakenga, et al., 1994; Patterson, 1981). Since the chlorophyll content is closely related to 

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425

plant dry matter production (Bottery and Bozzel; 1977), reduction in leaf chlorophyll content 

would decrease photosynthesis and thus total plant growth. 

Cell division, expressed as mitotic index, was significantly reduced in the presence of rice 

aqueous extracts (Table 8). Root extract of Mehr cultivar had higher inhibitory effect on mitosis 

compared to Amol-3 and leaf extract in both species. At 50 gl -1 , leaf extracts of Amol-3 and Mehr 

cultivars inhibited mitosis by 35 and 69%, respectively. Decreased DNA synthesis and thus cell 

division by 1,8-cineole has been reported by Koitabashi et al (1997). Crude volatile oil and 

aqueous leaf extract of Eucalyptus cumaldolensis severely reduced mitosis in root apical 

meristem of Allium cepa (Moradshahi et al., 2003). These results clearly show that reduced plant 

growth by allelochemicals in partly due to their effects on cell division. 

In this study, cultivars were genetically different. This could probably be a reason for their 

different allelopathic activity. The inhibition of barnyard grass germination by rice extracts may 

reflect the allelopathic potential of individual. The magnitude of allelopathic effects varied 

among the rice cultivars studied. Results of this study emphasize the variation in allelopathic 

activity among cultivars which has been mentioned by other studies (Kato-Nouguchi et al., 2008; 

Kato-Noguchi and Ino, 2005; Kato-Noguchi, 2004; Chung et al, 2003; Ahn and Chung, 2000; 

Olofsdotter and Navarez 1996; Dilday et al., 1991). In future studies, more rice cultivars should 

be screened for their allelopathic effects and allelochemical compounds released from all plant 

parts should be identified. 

Table 6 - Effects of aqueous extracts of two rice cultivars on leaf total peroxidase activity of 

barnyard grass (values are percent activity relative to control). † 

Leaf extract (g/l) Root extract (g/l) 

Rice cultivar 0 25 50 0 25 50 

Amol - 3 100A 115.2A 141.5B 100A 98.3A 120.1B 

Mehr 100A 126.6B 196.6C 100A 120.2B 132.9B 

† Means by the same letters are not significantly different (Duncan 5%) 

Table 7 - Effects of aqueous extracts of two rice cultivars on leaf total chlorophyll of barnyard grass 

(values are percent activity relative to control). † 



Amol - 3 3.65A 2.44B 3.14A 3.65A 3.11A 4.81B 

Mehr 3.52A 2.17B 2.66B 3.52A 2.48B 2.51C 

† Means by the same letters are not significantly different (Duncan 5%). 

Table 8 - Effects of aqueous extracts of two rice cultivars on mitotic index in root apical 

meristems of Allium cepa. † 



Amol - 3 6.49A 5.67A 4.19B 6.49A 4.39B 2.76B 

Mehr 6.49A 4.33B 2.02C 6.49A 5.01B 2.41B 

† Means by the same letters are not significantly different (Duncan 5%). 

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426

References 

Ahn JK & Chung IM (2000) Allelopathic potential of rice hulls on germination and seedling growth of barnyard 

grass. Agronomy Journal 92, 1162-1167. 

Arnon DI (1949) Copper enzymes in isolated chloroplasts. Polyphenol oxidase in Beta vulgaris. Plant Physiology 

24, 1-15. 

Baziramakenga R, Lrroux GD & Simard RD (1995) Effects of benzoic and cinnamic acids on membrane 

permeability of soybean roots. Journal of Chemical Ecology 21,1271-1285. 

Baziramakenga R, Simard R. R & Leroox GD (1994) Effects of benzoic and cinnamic acids on growth, mineral 

composition and chlorophyll content of soybean. Journal of Chememical Ecology 20, 2821-2833. 

Bottery BR & Bozzell RI (1977) The relationship between chlorophyll content and rate of photosynthesis in soybean. 

Canadian Journal of Plant Science 57, 1-5. 

Chou CH & Lin HJ (1976) Autointoxication mechanisms of Oryza sativa. L. Phytotoxic effects of decomposing rice 

residues in soil. Journal of Chemical Ecology 2, 353- 367. 

Chung IM, Kim KH, Ahn KJ, Lee SB, Kim SH & Hahn SJ (2003) Comparison of allelopathic potential of rice 

leaves, straw and hull extracts on barnyard grass. Agronomy Journal 95, 1063-1070. 

Chung IM, Ahn HJ & Yun SJ (2001) Assessment of allelopathic potential of barnyard grass on rice cultivars. Crop 

Protection 20, 921-928. 

Dali W, Ruixia M & Xiufen L (2000) A preliminary study on the allelopathic activity of rice germplasm. Scientia 

Agricultura Sinica 33, 94-96. 

Dilday RH, Nastasi P, Lin J & Smith Jr RJ (1991) Allelopathic activity in rice (Oryza sativa L.) against ducksalad 

[Heteranthera limosa (Sw.) willd.]. In : Sustainable Agriculture for the Great Plains J D Hanson et al. (Eds) 

pp. 193- 201. Proc., Beltsville, MD. 19- 20 Jan. ARS- 89. USDA- ARS, Springfield, MD. 

Dilday RH, Yan WG, Moldenhauer KAK & Gravois KA (1998) Allelopathic activity in rice for controlling major 

aquatic weeds. In: Allelopathy in rice. M. Olofsdotter (Ed) pp. 7-26. IRRI, Manila, Philippines . 

Ebana K, Yan W, Dilday RH, Namai H & Okuno K (2001) Variation in the allelopathic effect of rice with water 

soluble extracts. Agronomy Journal 93, 12- 16. 

Fay PK & Duke WB (1977) An assessment of allelopathic potential in Avena germplasm. Weed Science 25, 224- 

228. 

Hassan SM, Aidy IR, Bastawisi AO & Draz AE (1998) Weed management in rice using allelopathic rice varieties in 

Egypt. Proceedings of the Workshop on Allelopathy in Rice (ed Olofsdotter M) pp. 27- 37. Manila, 

Philippines. 25- 27 Nov. 1996. Int. Rice Res. Inst., Makati City, Philippines. 

Inderjit (1996) Plant phenolics in allelopathy Botanical Review 62, 186- 202. 

Juliono BO (1993) Rice in human nutrition. IRRI. Rome. 162 pp. 

Jung W S, Kim K H, Ahn J K Hahn S J & Chung I M (2004) Allelopathic potential of rice (Oryza sativa L.) 

residues against Echinochloa crus-galli. Crop Protection 23, 211-218. 

Kato-Noguchi H (2004) Allelopathic substance in rice root exudates: Rediscovery of momilactone B as an 

allelochemical. Journal of Plant Physiology 161, 271-276. 

Kato-Noguchi H & T Ino (2005) Concentration and release level of momilactone B in the seedlings of eight rice 

cultivars. Journal of Plant Physiology 162, 965-969. 

Kato-Noguchi H, T Ino & K Ota (2008) Secretion of momilactone A from rice roots to the rhizosphere. Journal of 

Plant Physiology 165, 691-696. 

Kim KU & Shin DH (1998) Rice allelopathy research in Korea . Proceedings of the Workshop on Allelopathy in Rice 

(ed Olofsdotter M) pp. 39-44. Manila, Philippines. 25- 27 Nov. 1996. Int. Rice Res. Inst., Makati city, 

Philippines. 

Koeppe DE (1972) Some reactions of isolated corn mitochondria influenced by Juglone. Physiologia Plantarum. 

27, 89-94. 

Koitabashi R, Suzuki T, Kawazu T, Sakai A, Kuroiwa H & Kuroiwa T (1997) 1,8-cineole inhibits root growth and 

DNA synthesis in the root apical meristem of Brassica campestris L. Journal of Plant Research 110, 1-6. 

Kong C, Xu X, Zhou B, Hu F, Zhang C & Zhang M (2004) Two compounds from allelopathic rice accession and 

their inhibitory activity on weeds and fungal pathogens. Phytochemistry 65, 1123-1128. 

Kong C, Wang P, Zhao H, Xu XH & Zhu YD (2008) Impact of allelochemical exuded from allelopathic rice on soil 

microbial community Soil biology and biochemistry 40, 1862-1869. 

Leather GR & Einhellig FA (1986) Bioassays in the study of allelopathy. In The science of allelopathy (eds Putnam 

AR & Tang CS), pp. 133- 145. John Wiley and Sons, New York . 

Lin J, Smith Jr RJ & Dilday RH (1992) Allelopathic activity of rice germplasm on weeds. In Proceedings of the 

Southern Weed Science Society. 45, 99. 

Posters 


427

Lin WX, Kim KU & Shin DH (2000) Rice allelopathic potential and its modes of action on barnyard grass. 

Allelopathy Journal 7, 215-224. 

Mac-Adem JW, Nelson C J & Sharp R E (1992) Peroxidase activity in the leaf elongation zone of tall fescue. Plant 

Physiology 99, 872-878. 

Maun MA & Barrett CH (1986) The biology of Canadian weeds. 77. Echinochloa crus-galli (L.) Beauv. Canadian 

Journal of Plant Science 66, 739- 759. 

Moradshahi A, Ghadiri H & Ebrahimikia F (2003) Allelopathic effects of crude volatile oil and aqueous extracts of 

Eucalyptus camaldulensis Dehr leaves on crops and weeds. Allelopathy Journal 12,180-192. 

Moradshahi A, Yaghmaee P & Ghadiri H (2002) Allelopathic potential of tree of heaven (Ailanthus altissima 

Swingle). Iranian Agricultural Research 21, 27-38. 

Mousavi S.Y (2000) Evaluation of Allelopathic potential of some northern Iranian rice varieties. M.Sc. Thesis, 

Agronomy Dept. Guilan University, Rasht, Guilan. 150 pp. 

Moustafa M.A, Boersma L & Kronstad WE (1996) Response of four spring wheat cultivars to drought stress. Crop 

Science 36, 982-986. 

Navarez D & Olofsdotter M (1996) Relay seeding technique for screening allelopathic rice (Oryza sativa). In 

Proceedings of 2nd International Weed Control Congress (eds Brown H et al.), pp. 1285- 1290. Copenhagen, 

Denmark. 25- 28 June 1996. Dep. of Weed Control and Pesticide Ecology, Slagelse, Denmark. 

Olofsdotter M & Navarez D (1996) Allelopathic rice for Echinochloa crus- galli control. In Proceedings of 2nd 

International Weed Control Congress (eds H. Brown H), pp. 1175-1181. Copenhagen, Denmark. 25- 28 June 

1996. Dep. of Weed Control and Pesticide Ecology, Slagelse, Denmark. 

Olofsdotter M, Navarez D & Rebulanan M (1997) Rice allelopathy: Where are we and how far can we get? In The 

1997 Brighton Crop Protection Conference pp. 99-104. Brighton, UK. 17-20 Nov. 1997. Weeds. Vol. 1. The 

British Crop Protection Council, Brighton, UK. 

Olofsdotter M, Navarez D, Rebulanan M & Stereibig JC (1999) Weed supperssing rice cultivars- does allelopathy 

play a role? Weed Research 30, 441- 454. 

Patrick Z H & Koch L.W (1958) Inhibition of respiration, germination, and growth by substances arising during the 

decomposition of certain plant residues in the soil. Canadian Journal of Botany 36, 631-647. 

Patterson D T (1981) Effects of allelopathic chemicals on growth and physiological responses of soybean (Glycine 

max). Weed Science 29, 53-59. 

Pheng S, Adkins S, Olofsdotter M & Jahn G (1999) Allelopathic effects of rice (Oryza sativa L.) on the growth of 

awnless barnyard grass (Echinochloa colona L.): A new form for weed management. Cambodian Journal of 

Agriculture 2,42- 49. 

Putnam AR & Tang CS (1986) Allelopathy: state of the science. In The science of allelopathy (eds Putnam AR & 

Tang CS), pp. 1-19 New York: John Wiley and Sons. 

Raju R.A (2000) Glimpse of Rice Technology. Agrobios (India). 247 pp. 

Rao VS (2000) Principles of Weed Science. 2 nd Ed. Science Publishers, Inc., NH, USA. 555 pp. 

Rice EL (1984) Allelopathy. 2 nd Ed. New York: Academic Publishers. 424 pp. 

Ruzin S E (1999) Plant Micro technique and Microscopy. Oxford, UK: Oxford University Press.322pp. 

Statistical Analysis Systems (2000) Statistical analysis software. Version 8. Cary, NC: Statistical Analysis Systems 

Institute. 

Steuter AA, Mozafar A & Goddin JR (1981) Water potential of aqueous polyethylene glycol. Plant Physiology 67, 

64-67. 

Young CC, Zhu Thorne LR and Waller GR (1989) Phytotoxic potential of soils and wheat straw in rice rotation 

cropping systems of subtropical. Taiwan. Plant and Soil 120, 95-101. 

Zimdahl R.L (1999) Fundamentals of Weed Science. 2 nd Ed. Academic Publishers, New York. 556 pp. 

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428

Solanum elaeagnifolium, an emerging invasive alien weed in the Mediterranean region and 

Northern Africa 

Javid Kashefi 

USDA ARS EBCL, Tsimiski 43, 7 th floor, 54623 Thessaloniki, Greece 

E-mail: javidk@afs.edu.gr 

Solanum elaeagnifolium (Solanacea) is native to the Southern United States and Northern Mexico 

and an invasive alien weed to North and Central Greece with rapid expansion to other regions. 

Because of its deep root system, resistance to drought and lack of natural enemies which could 

keep its population under control, the weed is becoming a nightmare for farmers and ranchers in 

the infested areas. In protected areas and national parks the weed is heavily suppressing the 

endemic plant population and is affecting the balance of natural ecosystems in these areas. 

Climate change in the region with increase of temperature and reduction of rain fall can affect 

dramatically the speed of expansion of the weed in the Balkan Peninsula and other countries in 

southern Europe. One of the major obstacles to controlling the weed is the high number of 

commercial, medicinal and ornamental plants which are closely related to the weed. 

In an effort to reduce the weed‘s population and its spread, USDA ARS European biological 

control laboratory and Benaki Plant Pathology Institute recently started a joint biological control 

program to investigate the possibility of introduction and testing of the weed‘s natural enemies 

from United States and to study their suitability for release in Greece and the European Union to 

stop the spread of the weed. 

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429

Evaluation of Indigenous Fungi as Potential Biological Control Agents to Cocklebur 

(Xanthium strumarium) 

HE Alloub and TT Abdeldaim 

Department of Crop Protection, Faculty of Agricultural Sciences, University of Gezira, P. O. Box 

20, Medani, Sudan. E-mail: halaalloub@yahoo.com 

Introduction 

Cocklebur became a serious weed, which is newly introduced in Sudan. This 

study was conducted to investigate the feasibility of using indigenous fungal 

plant pathogens as biological control agents to control cocklebur. Different 

infested locations were surveyed for collection of naturally infected plants of 

cocklebur. Fungi belonging to eight genera were found associated with the 

weed. They were identified as: Alternaria helianth, Bipolaris sp., Cercospora 

sp., Curvularia lunata, Exserohilum rostratum, Fusarium oxysporum, Phoma 

sp. and a Rhizectonia sp. 

Isolated fungi were tested for pathogenisity and host specificity. Alternaria 

helianthi, Bipolaris sp.,Cercospora sp., Exserohilum rostratum and Phoma sp. 

were highly pathogenic to cocklebur when applied on the weed at 2-3 leaf 

stage. Among them, Cercospora sp. showed good degree of selectivity towards 

the weed when initially screened against cotton, sorghum, sunflower, tomato or 

Sonchus corntus. Furthermore, the effect of growth age of cocklebur seedlings 

on disease development by Cercospora sp. was studied and the result showed 

that growth age had a significant effect on disease development, 2 to 5 leaf 

stages were the most susceptible stages to Cercospora sp. infection. Therefore, 

Cercospora sp. may be considered as a potential biocontrol agent to cocklebur. 

Weeds constitute a serious problem to crop production. Yield losses due to competition by 

weeds were estimated to 12 % worldwide (Pimental and Pimental, 1997). Xanthium strumarium 

L. is a serious annual broad leaf weed newly introduced in Sudan and fastly became problemetic 

in many agricultural areas, waste lands and/or along water canals and river banks. Cocklebur is a 

problem in sheep farming, because the young seedlings are poisonous to grazing animals, and 

burs cling on wool reduce its quality. 

The most common methods used for cocklebur control are tillage and hand weeding, Several 

herbicides can effectively control the weed. However, most non-selective herbicides do not 

persist in the soil to control the new flushes of weed seedlings. 

Posters 

2 nd Recently, there has been increased interest in developing new approaches for controlling 

weeds due to high cost of hand weeding, lack of suitable selective herbicides, concerns to the 

society and the environment associated with extensive use of chemicals. Moreover, the 

continious use of some herbicides has led to development of herbicide resistance in some weed 

species worldwide. Therefore, safe and improved weed management strategies are needed. The 

use of indigenous fungi for biological control of weeds or mycoherbicides could be an alternative 

for cocklebur control. The prospect of developing mycoherbicides for control of cocklebur in 

430 


Sudan is promising since there is no selective measure for its control. Therefore, the present 

research was undertaken to study the feasibility of using indigenous fungi as mycoherbicides for 

cocklebur control in Sudan. 


Collection, Isolation and Identification of Fungi 

Field trips were made to collect cocklebur plants with disease symptoms from naturally 

infected populations in six infested regions in Sudan namely, Gadarif, Rahad, Gezira, Damazin, 

Rosaris and Zeidab. Plant parts from each collection were dried in a plant press, cut into 2 mm 2 

and then stored in envelopes at 4 o C for processing in the laboratory. 

Plant parts were surface sterilized in 0.5% sodium hypochlorite solution for three minutes, 

rinsed twice with distilled water and placed on potato dextrose agar (PDA) in 9 cm diameter 

sterile petri dishes. Three days after incubation, fungi growing from lesions were transferred to 

fresh PDA in petri dishes. Pure isolates were made by 2 successful transfers of conidia to fresh 

PDA and were maintained on PDA slant in test tubes as stock to be used later for inoculation. 

The isolated fungi were identified based on their colony characters, conidial morphology and 

growth characteristics on media. For each isolate, 25 conidia were measured. 

Inoculum production 

A small piece of agar mycelium from the stock culture of each fungus was transferred to PDA 

in 9 cm diameter petri dishes. The plate were sealed with parafilm and incubated at room 

temperature (25-28 o C) for three days under a 12 hrs light provided by 15W fluorescent lamp. 

Small piece of mycelium (6 mm diameter) from the margins of the actively growing colonies 

were placed in the center of PDA petri dishes, sealed with parafilm and incubated at room 

temperature under a 12 hrs light provided by 15W fluorescent lamp to induce sporulation. Ten 

days after incubation, inoculum was prepared for each isolate by adding 10 ml distilled water 

containing 0.01% Tween 20 to the petri dish and scraping the spores from the surface of the 

colonies with a glass slide. Resulting suspensions were filtered though 2 layers of cheesecloth 

and the final concentration of 1 x 10 6 conidia/ml was adjusted with water containing 0.01% 

Tween 20 with a haemocytometer. 

Pathogenicity of Isolated Fungi 

To determine pathogenicity of isolates, eight seeds of cocklebur were planted in 10 cm 

diameter plastic pots in sandy clay soil. The soil was steam sterilized for one hour at 120 o C. The 

pots were maintained in a glasshouse at a temperature range of between 25 to 30 o C and 75 to 

90% relative humidity. Emerging seedlings of each group were thinned to 3-seedlings per pot. 

For each of the eight isolates, 3-4 leaf stage seedlings of cocklebur were sprayed to run off (10 

ml) with 2 x 10 6 conidia/ml suspension containing 0.01% Tween 20 using a hand sprayer. 

Control plants were sprayed with distilled water containing 0.05% Tween 20. Inoculated and 

control plants were enclosed in plastic bags and sealed for 24 hrs. The pots were arranged in 

CRD with 4 replications. 

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431

Disease severity (DS) was used to evaluate disease development on cocklebur seedlings. DS 

was rated daily for 30 days after inoculation as percentage of leaf area affected based on a scale 

of 0-4, where: 0 = no symptoms; 1 = < 25% of leaf area affected; 2 = 26-50% of leaf area 

affected; 3 = 51-75% of leaf area affected; 4 = 76-100% of leaf area affected. 

∑[(scale value) x (Number of plants/scale)] 

% DS= x 100 

[(Total number of plants) x (highest scale)] 

The pathogens were reisolated from lesions and the test was repeated to confirm koch‘s 

postulates. 

Primary Host Range Test 

Pathogenic isolates were tested against (a) cocklebur as a positive control, (b) three important 

field crops in Sudan namely, cotton cv Acala, sorghum cv Wad Ahmed, and a sunflower variety, 

(c) tomato as an important vegetable crop and (d) Sonchus corntus as one of the common weeds. 

Test plants were planted in 9 cm diameter plastic pots in a sterilized sandy clay soil. All plants 

were maintained in the glasshouse. Test plants at 3 to 4 leaf stages were inoculated with 2 x 10 6 

conidia/ml containing 0.01% Tween 20. Control plants were sprayed with distilled water 

containing 0.01% Tween 20. Both inoculated and control plants were covered with plastic bags 

for 24 hr and arranged in a CRD with 4 replications. DS and disease index (DI) were used to 

measure disease development of each isolate on cocklebur seedlings. DS was rated daily as in the 

pathogenicity test. DI was calculated from the disease severity scale as follows: 

% DI= 

∑[(scale value) x (Number of plants/scale)] 

(Total number of plants assessed) 

The value of DI was rounded to whole number. 0= immune plant; 1= resistant plant; 2 = 

tolerant plant; 3= severe damage; 

4= complete death 

Efficacy of Cercospora sp. on different Cocklebur Growth Stages 

Seedlings of cocklebur at 2-3, 3-4, 4-5, 6-7 and 9-10 leaf stages grown in 9 cm diameter 

plastic pots in a sterilied sandy clay soil were inoculated with 2 x 10 6 conidia/ml suspension 

containing 0.01% Tween 20. A check with distilled water containing 0.01% Tween 20 was 

included. After inoculation, the plants were covered with clear polyethylene bags for 24 hr. DS 

was rated daily and a final rating was made at 15 days. 

Statistical Analysis 

All experiments were done twice. Data were subjected to ANOVA. Percentage data were 

arcsine transformed before statistical analysis. Treatment means were tested using Duncan‘s 

multiple range test at the 5% level of significance. 

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Results 

Collection, Isolation and Identification of Fungi 

Table 1 showed the 10 locations in the six infested regions in Sudan from which fungi found 

associated with cocklebur were isolated. Seven different species of pathogenic fungi were 

isolated and identified as: Alternaria helianthi; Bipolaris sp.; Cercospora sp.; Curvularia lunata, 

Exserohilum rostratum; Fusarium oxysporum; Phoma sp. and a Rhizectonia sp. C. sp.; E. 

rostratum; F. oxysporum; Ph. sp. and Rh. sp.; were the most dominant isolated from all locations 

sampled (Table 1). 

Table 1 - Results of surveys undertaken in Sudan for potential fungi on cocklebur 

Region Location 

Habitat 

Isolated Fungi 

Gadarif Sorghum field Rhizectonia sp. 

Damazin 

Rosaris 

Gezira 

Rahad 

Ziedab 

Maize field 

Annual crops field 

Along riverbank 

Fruit Orchard 

Along roadsides 

Okra field 

Along riverbank 

Annual crops field 

Along roadsides 

Alternaria helianthi Bipolaris sp., Cercospora sp., 

Cuvularia lunata, Exserohilum rostratum and 

Rhizectonia sp. 

Alternaria helianthi, Bipolaris sp., Cercospora sp., 

Cuvularia lunata, Exserohilum rostratum and 

Rhizectonia sp. 

Cercospora sp., Phoma sp., F. oxysporum 

and Rhizectonia sp. 

Cercospora sp., Eserohilum rostratum, F. oxysporum 

and Phoma sp. 

F. oxysporum 

Pathogenicity of Isolated Fungi 

Results of preliminary screening for pathogenicity against cocklebur were shown in Table 2. 

Significant differences in pathogenicity were observed. A. helianthi; B. sp.; C. sp., E. rostratum 

were highly damaging resulting in 100% DS followed by Phoma sp. isolate and lesser 

pathogenicity were obtained by C. lunata and F. Oxysporum. Rh. sp. was non-pathogenic to 

cocklebur and was not evaluated further in this study. 

Primary Host Range Test 

Reactions of tested plants to five isolates are summarized in Table 3. All tested isolates were 

highly pathogenic to cocklebur. However, Alternaria helianthi, Bipolaris sp., Exserohilum 

rostratum and the Phoma sp. severely damaged or completely killed sunflower. Cercospora sp. 

showed good degree of selectivity towards the weed when initially screened against cotton, 

sorghum, sunflower, tomato or Sonchus corntus. The isolate caused severe infection to cocklebur, 

while only producing slight to moderate infections to other plants tested. The results from the 

primary screening suggest that Cercospora sp. has potential as biocontrol agent against 

cocklebur. 

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Table 2 - Pathogenicity of the isolated fungi on cocklebur 

Isolates Disease severity* 

Alternaria helianthi 100 a 

Bipolaris sp. 100 a 

Cercospora sp 100 a 

Curvularia lunata 50 c 

Exserohilum rostratum 100 a 

Fusarium oxysporum 48 c 

Phoma sp. 81.7 b 

Rh. sp. 0.0 d 

Se ± 0.06 

* Based on a scale: 0 = no symptoms; 1 = < 25% of leaf area affected; 2 = 26-50% of leaf area 

affected; 3 = 51-75% of leaf area affected; 4 = 75-100% of leaf area affected. Means followed by 

the same letter are not significantly different at 0.05% level using DMRT. 

Table 3 - Reactions of tested plant species on primary host range test to the different isolates 

Common Cultivar Isolated disease severity index * 

Tested plants Name 

A. Bipolaris Cercospora E. Phoma sp. 

helianthi sp. sp. rostratum 

Lycopersicon Tomato Castle 0 0 0 0 0 

esculentum 

rock 

Helianthus 

annuus 

Sunflower Baran 4 3 0 4 3 

Gossypium 

hirsutum 

Cotton Acala 0 0 0 0 0 

Sorghum bicolor Sorghum Wad 

Ahmed 

2 0 0 2 0 

Sonchus 

coruntus 

Molita Baladi 3 2 1 0 1 

Xanthium 

strumarium 

Cocklebur 4 4 4 4 4 

*0=immune; 1= resistant; 2= tolerant; 3= severe damage; 4=death. 

Efficacy of Cercospora sp. on different Cocklebur Growth Stages 

Growth age of cocklebur seedlings had a significant effect on disease development (Table 4). 

Cocklebur seedlings at 2-3 and 3-4 leaf stages (Plate 1) at time of inoculation were completely 

killed by Cercospora. sp. with 2 x 10 6 conidia/ml suspension containing 0.01% Tween 20 (DS 

100%) followed by 4-5 leaf stage seedlings (56.3%). The lowest disease severity was observed 

on 9-10 leaf stage seedlings (25%). 

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434

Table 4 - Efficacy of Cercospora sp. on different cocklebur growth stages 

Growth stage Disease severity* 

2-3 leaves 100 a 

3-4 leaves 100 a 

4-5 leaves 56.3 b 

6-7 leaves 31.3 c 

9-10 leaves 25.0 d 

Se ± 0.3 

* Based on a scale: 0 = no symptoms; 1 = < 25% of leaf area affected; 2 = 26-50% of leaf area 

affected; 3 = 51-75% of leaf area affected; 4 = 75-100% of leaf area affected. Means followed by 

the same letter are not significantly different at 0.05% level using DMRT. 

A: Control B: Treated plant 

Figure 1 - Cocklebur seedlings (3-4 leaf stage) inoculated with 2 x 10 6 conidia/ml of 

Cercospora sp. containing 0.01% Tween 20. 

Discussion 

A B 

In the present study five isolated fungi were highly pathogenic to cocklebur. However, in 

development of a bioherbicide safety to non-target plants or host specificity is one of the most 

important factors. Our findings showed that Alternaria helianthi, Bipolaris sp., Exserohilum 

rostratum and the Phoma sp. were non selective to sunflower which is an important oil crop in 

the Sudan. Cercospora sp., showed selectivity to cocklebur. However, further screening of this 

isolate against more plant species or cultivars is needed to insure adequate specificity towards the 

weed. 

In agreement with our findings, fungi belonging to the genera Alternaria, Cercospora, 

Curvularia and Fusarium, were reported associated with cocklebur (Roy et. al., 1999). Abbas et. 

al. (1999), reported that Alternaria helianthi was highly pathogenic to cocklebur and sunflower. 

In Brazil, a local isolate of Cercospora apii was reported pathogenic to cocklebur (Rocha et. al., 

2007). In previous studies in Sudan powdery mildew and Exserohilum rostratum have been 

found associated with cocklebur (Gamiel et al., 2002; Ahmed and Eltayeb 2009). 

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435

From the present study, it is apparent that Cercospora sp., applied as 2 x 10 6 conidia/ml 

suspension containing 0.01% Tween 20 has a strong potential to be developed as a 

mycoherbicide for cocklebur due to its ability to kill the seedlings of cocklebur in a few days and 

safety to economically important crops in the Sudan. These results indicated that Cercospora sp. 

was effective in controlling cocklebur seedlings under glasshouse conditions. 


The authors are grateful to Agricultural Research Corporation, Damazin for the invaluable 

assistance during the surveys. 

References 

Abbas HK, Pantone DJ & Paul RN (1999) Characteristics of multiple-seeded cocklebur: a biotype of common 

cocklebur (Xanthium strumarium L.). Weed Technology 13, 257–263. 

Ahmed NE and Eltayeb SM (2009) leaf blight: A new disease of Xanthium strumarium cause by Exserohilum 

rosturatam in sudan. University of Khartoum Journal of agricultural science 17, (3):407 - 412. 

Gamiel SA, Ahmed NE, Inanaga YS & Sugimoto Y (2002) More important weed species as a host plants of powdery 

mildew. Journal of Agricultural Sciences 10, 134-141. 

Pimental D & Pimental M (1997) Food, energy and society options and solutions. Network Focus 3, 52-59. 

Roy K.W, Miller WA & Mc Len LS (1994). Survey of pathogenic genera of fungi on foliage weeds in Mississippi. 

Canadian Journal of Plant Pathology 16, 25-29. 

Rocha FB, Pereira OL & Brreto RW (2007) Cerecospora apii causing leaf spots in two Brazilian toxic weeds: 

Solanum glaucophyllum and Xanthium stramurium. Barazilian Journal of Microbiology 38, 142-144. 

Posters 


436

E-mails of participants 

E-mails of Participants 


437

E-mails of participants 

Armenia Mr. George Fayvush 

Institute of Botany of National Academy of Sciences of Armenia 

E-mail: gfayvush@yahoo.com 

Australia Ms. Judith Lorraine Fisher 

University of Western Australia/Fisher Research, 

E-mail: ecologist@waanthropologist.com 

Azerbaijan Ms. Vasila Salamova 

State Phytosanitary Control Service, 

E-mail: vasila-s@rambler.ru, dfnx@mail.az 

Bulgaria Mr. Vladimir Vladimirov 

Institute of Botany Bulgarian Academy Of Sciences, 

E-mail: vdvlad@bio.bas.bg 

Chile Prof. Ramiro O. Bustamante, 

University Of Chile, E-mail: ramironte@gmail.com 

Croatia Ms. Maja Kravarscan 

Croatian Centre for Agriculture, Food and Rural Affairs, Institute for Plant 

Protection, E-mail: maja.kravarscan@hcphs.hr 

Czech 

Republic 

Mr. Jan Samanek 

State phytosanıtary administration, E-mail: jan.samanek@srs.cz 

France Mr. Pierre Ehret 

French Plant Protection Organization, 

E-mail: pierre.ehret@agriculture.gouv.fr 

Mr. Guillaume Fried 

Laboratoire National de Protection des Végétaux, 

E-mail: fried@supagro.inra.fr 

Ms. Enora Leblay 

Federation des Conservatoires botaniques nationaux, E-mail : 

enora.leblay@fcbn.fr 

Ms. Emilie Mazaubert 

CEMAGREF, E-mail: emilie.mazaubert@cemagref.fr 

Greece Ms. Garifalia Economou-Antonaka 

Agricultural University of Athens, 

E-mail: cagr2ecg@noc.aua.gr; economou@aua.gr 



438

Mr. Javid Kashefi 

USDA ARS EBCL, E-mail: javidk@afs.edu.gr 

Prof. Eleni Kotoula-Syka 

Democritus University of Thrace, E-mail: kotoulaeleni@yahoo.gr 

Prof. Petros Lolas 

Universty Thessaly, E-mail: lolaspet@agr.uth.gr 

Hungary Ms. Martha Nelima Okumu 

University of Pannonia, E-mail: nelmak2212@yahoo.com 

India Prof. Ratikanta Ghosh 

Faculty of Agriculture, Bidman Chandra Krishi, 

E-mail: rajbckv@rediffmail.com 

Prof. Inderjit Singh 

Delhi University, E-mail: inderjit@cemde.du.ac.in 

Iran Ms. Leila Jafari 

Hormozgan University, E-mail: leilajaf@yahoo.com 

Ms. Mitra Ghotbi 

Shahed University of Tehran, E-mail: mitra.ghotbi@gmail.com 

Ms. Marjan Ghotbi 

Azad University, Tehran, Iran, E-mail: marjan.ghotbi@gmail.com 

Israel Ms. Mildred Quaye 

Hebrew University of Jerusalem, E-mail: mildyq@yahoo.com 

Mr. Tuvia Yaacoby 

Plant Protection and Inspection Services, E-mail: tobyy@moag.gov.il 

Italy Mr. Giuseppe Brundu 

University of Sassari, Department of Botany, Ecology and Geology 

E-mail: gbrundu@tin.it 

Mr. Roberto Crosti 

ISPRA Dipartimento Difesa della Natura, 

E-mail: roberto.crosti@isprambiente.it 

Ms. Anna Mazzoleni 

Parco del Basso Corso del Fiume Brembo, 

E-mail: anna.mazzoleni@gmail.com 



439

Mr. Antonio Perfetti 

Ente Parco Regionale Migliiarino San Rossore Massaciuccoli, 

E-mail: a.perfetti@sanrossore.toscana.it 

Ms. Lina Podda 

Department of Botanical Sciences, University of Cagliari, 

E-mail: linap68@yahoo.it 

Lithuania Ms. Ligita Balezentiene 

Lıthuanian unıversity of agriculture, E-mail: ligitaba@gmail.com 

Malaysia Prof. Baki Bakar 

Institute of Biological Sciences, University of Malaya, 

E-mail: baki_um@yahoo.com 

Morocco Prof. Mohamed Bouhache 

Institut Agronomique et Vétérinaire Hassan II, 

E-mail: m.bouhache@gmail.com; m.bouhache@iav.ac.ma 

Prof. Abdelkader Taleb 

Institut Agronomique et Vétérinaire Hassan II, E-mail: a.taleb@iav.ac.ma; 

abdeltaleb@yahoo.fr 

Portugal Ms. Elizabete Marchante 

Centre for Functional Ecology, University of Coimbra, 

E-mail: elizabete.marchante@gmail.com 

Saudi 

Arabia 

Mr. Thobayet Alshshrani 

King Saud University, E-mail: thobayet@yahoo.com 

Serbia Ms. Dragana Marisavljevic 

Institute for plant protection and environment, 

E-mail: marisavljevicd@yahoo.com 

Ms. Danijela Pavlovic 

Insitute for plant protection and environment, 

E-mail: pavlovicdm@gmail.com 

Ms. Sava Vrbnicanim 

Insitute for plant protection and environment, E-mail: sava@agrif.bg.ac.rs 

Slovakia Prof. Pavol Elias 

Dept. Of Ecology, Slovak Agricultural University, 

E-mail: pavol.elias@uniag.sk 



440

Slovenia 

South 

Africa 

Mr. Mario Lesnık 

Faculty of Agriculture and Life Sciences Maribor, 

E-mail: mario.lesnik@uni-mb.si 

Ms. Mirijam Gaertner 

Stellenbosch University, E-mail: gaertnem@sun.ac.za 

Mr. Philip Ivey 

Early Detection Programme, SANBI, E-mail: p.ivey@sanbi.org.za 

Ms. Genevieve Thompson 

Stellenbosch University, E-mail: gen@sun.ac.za 

Ms. Hilary Geber 

University of the Witwatersrand, E-mail: hilary.geber@wits.ac.za 

Ms. Ernita van Wyck 

South African National Biodiversity Institute, 

E-mail: Er.vanWyk@sanbi.org.za 

Mr John Wilson 

Stellenbosch University, E-mail: jrwilson@sun.ac.za 

Sudan Mr. Abdel Gabar Babiker 

Sudan University of Science and Technology, E-mail: agbabiker@yahoo.com 

Ms. Hala Eltahir Mahmoud Alloub 

University of Gezira, E-mail: halaalloub@yahoo.com 

Switzerland Mr. Christian Bohren 

Agroscope ACW, E-mail: christian.bohren@acw.admin.ch 

Tunisie Prof. Mounir Mekki 

Institut Superieur Agronomique, E-mail: Mekki.mounir@iresa.agrinet.tn 

Turkey Mr. Necmi Aksoy 

Duzce University,Faculty of Forestry, E-mail: necmiaksoy@duzce.edu.tr 

Mr. Güven Algün 

Quarantine Directorate, Trabzon, E-mail: guvenalgun@hotmail.com 

Mr. Ünal Asav 

Quarantine Directorate, Trabzon, E-mail: unalasav@hotmail.com 



441

Mr. İsmail Aslan, 

Province Directorate of Agriculture Ministry, Trabzon, 

E-mail: i.aslan@hotmail.com 

Ms. Selma Aydın 


E-mail: selma47aydin@hotmail.com 

Mr. Sinan Aydin 


E-mail: sinanaydin59@hotmail.com 

Ms.Nuray Aydoğan 


E-mail: nurozan@hotmail.com 

Mr. Osman Nuri Baki 


E-mail: osmannuribaki@hotmail.com 

Mr. Muharrem Bozoğlu 

Quarantine Directorate, Trabzon, E-mail: mbozoğlu61@hotmail.com 

Ms.Fikriye Çakır 


E-mail: fikriye52@hotmail.com 

Mr. Salih Çolak 

Quarantine Directorate, Trabzon, E-mail : scolak1974@hotmail.com 

Mr. Bektaş Erdoğan, 


E-mail: berdo60@hotmail.com 

Ms. Hümeyra Aykul Gepdiremen 

Ege University, E-mail: humeyragepdiremen@hotmail.com 

Mr. İhsan Güner 

Quarantine Directorate, Trabzon, E-mail : ihsanguner61@hotmail.com 

Mr. Doğan Işık 

Karadeniz Agricultural Research Institute, Samsun 

E-mail: zorludogan@hotmail.com 



442

Mr. Koray Kaçan 

Bornova Plant Protection Research Institute, Izmir, 

E-mail: koraykacan@yahoo.com 

Mr. B. Ali Kadı 


E-mail: bitkikoruma61@hotmail.com 

Prof İzzet Kadıoğlu 

Gazi Osman Paşa University, Tokat, E-mail: izzetk@gop.edu.tr 

Ms. Songül Kadıoğlu 

Province Directorate of Agriculture Ministry, Rize, 

E-mail: s.kadioglu@hotmail.com 

Mr. İsmet Kahraman 


E-mail: ismetkahraman_61@hotmail.com 

Mr. Ali Yaşar Kan 


E-mail: aliyasarkan@hotmail.com 

Ms. Ayşe Kaplan 

Zonguldak Karaelmas University, E-mail: a_kaplan007@yahoo.com 

Ms. İlhan Kaya 

Yüzüncü Yıl University, Van, E-mail: ilhank@yyu.edu.tr 

Mr. Mustfa Mazlum 


E-mail: trabzon.idari@tarimnet.gov.tr 

Mr. Peiman Molei 

Ege University, İzmir, E-mail: molaei.p59@gmail.com 

Prof. Yıldız Nemli 

Ege University, İzmir, E-mail: yildiz.nemli@ege.edu.tr 

Ms. A. Hülya Ofluoğlu 

Quarantine Directorate, Trabzon, E-mail : hulya-ofluoglu@hotmail.com 

Mr. Sedat Saral 

Eastern Blacksea Development Project, Trabzon, 

E-mail: saralsedat@hotmail.com 



443

Mr. Tansel Serim 

General Directorate of Research, Ministry of Agriculture, Ankara, 

E-mail: tserim@tagem.gov.tr 

Mr. Vedat Sizer 

Bayer Türk AS, Şanlıurfa, E-mail: vedat.sizer@hotmail.com 

Mr. Harun Sümbül 

Province Directorate of Agriculture, Trabzon E-mail: 

61BitkiKoruma@kkgm.gov.tr 

Mr. Süleyman Türkseven 

Ege University, İzmir, E-mail: suleyman.turkseven@ege.edu.tr 

Mr. Çetin Uçak 

Eastern Blacksea Development Project, Trabzon, 

E-mail: cetinucak25@hotmail.com 

Mr. Emin Uğurlu 

Celal Bayar Unıversıty, Manisa, E-mail: ugurlu@yahoo.com 

Mr. İlhan Üremiş 

Mustafa Kemal University, Antakya, E-mail: iuremis@yahoo.com 

Mr. Servet Uslu 

Quarantine Directorate, Trabzon, E-mail: servetuslu61@hotmail.com 

Prof. Yusuf Yanar 

Gazi Osman Paşa University, Tokat, E-mail: yyanar@gop.edu.tr 

Ms. Ayşe Yazlık 

Atatürk Central Horticultural Research Institute, Yalova, 

E-mail: ayseyazlik77@hotmail.com 

Mr. Reyyan Yergin 

Yüzüncü Yıl University, Van, E-mail: reyyanyergin@yyu.edu.tr 

Mr. Anıl Yılmaz 

Antalya Exporter Unions General Secretariat, E-mail: yilmaza@aib.gov.tr 

Mr. Erdal Yiğci 


E-mail: eyigci@hotmail.com 



444

Mr. Hüseyin Zengin 

Igdır University, E-mail: drzengin@hotmail.com 

UK Prof. Vernon Hilton Heywood 

University of Reading, E-mail: vhheywood@btinternet.com 

Mr. Stephen Jury 

University of Reading, E-mail: s.l.jury@reading.ac.uk 

USA Prof. Kassim Al-Khatib 

University of California, E-mail: kalkhatib@ucdavis.edu 

Council of 

Europe 

Mr. Eladio Fernandez Galiano 

Council of Europe, Bern Convention, 

E-mail: eladio.fernandez-galiano@coe.int 

EEA Mr. Ahmet Uludağ 

European Environment Agency, E-mail: ahmet.uludag@eea.europa.eu, 

ahuludag@yahoo.com 

EFSA Ms. Sara Tramontini 

Europen Food Safety Authority, E-mail: Sara.TRAMONTINI@efsa.europa.eu 

EPPO Ms. Sarah Brunel 

EPPO / OEPP, E-mail: brunel@eppo.fr 

IUCN Mr. Riccardo Scalera 

IUCN Invasive Species Specialist Group, E-mail: scalera.riccarda@gmail.com 

NOBANIS Ms. Melanie Josefsson 

Swedish Environmental Protection Agency, E-mail: 

melanie.josefsson@snv.slu.se 



445



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